TRIARYL BORANE CATALYSTS AND METHOD FOR SELECTIVE HYDROSILYLATION OF ESTERS AND LACTONES USING SAID CATALYSTS

Abstract

The present invention relates to a catalytic process for the partial reduction of esters or lactones to silyl acetals, which upon hydrolysis give aldehydes, using silanes as reducing agents, preferably triethylsilane (TESH) or 1,1,3,3-tetramethyldisiloxane (TMDS), in the presence of novel triaryl borane type catalysts. More specifically, the present invention relates to novel triaryl borane type catalyst compounds of formula (I) which can be applied for the partial reduction of an ester or lactone to a silyl acetal. In the formula R.sub.1, R.sub.1, R.sub.5, R.sub.5 and R.sub.6 are groups having small steric demand and R10 is a group having large steric demand. The invention also relates to N a method for the preparation of aldehydes or lactols wherein said method comprises the following steps: i) an ester or lactone is reacted with a silane in the presence of a compound of formula (I) to obtain a silyl acetal; ii) the obtained silyl acetal is hydrolysed with acidic or fluoride containing reagent to form an aldehyde or lactol; iii) optionally, the resulting aldehyde or lactol is separated and purified.

##STR00001##

Claims

1. A compound of general formula (I) ##STR00064## wherein B is boron; A ring and A ring, independently from each other, are aryl or heteroaryl groups, wherein R.sub.1 and R.sub.1 are independently selected from the group consisting of H, D and F; R.sub.5 and R.sub.5 are independently selected from the group consisting of H, D and F; each R.sub.2, R.sub.3, R.sub.4, R.sub.2, R.sub.3 and R.sub.4 are independently selected from the group consisting of H, D, F, Cl, Br, I, SF.sub.5, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and heteroaryl groups, where the alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and heteroaryl groups are optionally substituted; C ring is aryl group, wherein R.sub.6 is selected from the group consisting of H, D and F; R.sub.10 is selected from the group consisting of Cl, Br, I, SF.sub.5, alkyl, cycloalkyl, alkenyl, cycloalkenyl, phenyl, heteroaryl and Si(R.sub.15).sub.3 groups, where the alkyl, cycloalkyl, alkenyl, cycloalkenyl, phenyl and heteroaryl groups are optionally substituted with one or more substituent(s) selected from the following group: alkyl, halogen, hydroxyl and alkoxy, where the alkyl and alkoxy is optionally substituted with halogen); where R.sub.15 groups are selected, independently from each other, from the following scope: alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and heteroaryl groups, where the alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and heteroaryl groups are optionally substituted; R.sub.7, R.sub.8 and R.sub.9 are independently selected from the group consisting of H, D, F, Cl, Br, I, SF.sub.5, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and heteroaryl groups, where the alkyl, cycloalkyl, alkenyl, cycloalkenyl and heteroaryl groups are optionally substituted, with the proviso that when R.sub.1 to R.sub.5, R.sub.1 to R.sub.5 and R.sub.6 to R.sub.9 are F, then R.sub.10 is not pentafluorophenyl or methyl group; when R.sub.1 to R.sub.5, R.sub.1 to R.sub.5 and R.sub.6 to R.sub.9 are H, then R.sub.10 is not phenyl; when R.sub.1 to R.sub.5, R.sub.1 to R.sub.5 are F and R.sub.6 to R.sub.9 are H, then Rio is not methyl; when R.sub.1 to R.sub.5, R.sub.1, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8 are H, R.sub.2 and R.sub.9 are Br, then R.sub.10 is not Cl; when R.sub.1, R.sub.5, R.sub.1, and R.sub.5 are H, R.sub.2, R.sub.4, R.sub.2 and R.sub.4 are CF.sub.3, R.sub.6 and R.sub.8 are F, and R.sub.7 and R.sub.9 are H, then R.sub.10 is not Cl; when R.sub.1, R.sub.5, R.sub.1 and R.sub.5 are H, R.sub.2, R.sub.4, R.sub.2, R.sub.4, R.sub.6 and R.sub.9 are CF.sub.3, then R.sub.10 is not H; when R.sub.1, R.sub.2, R.sub.4, R.sub.5, R.sub.1 R.sub.2, R.sub.4 and R.sub.5 are F, R.sub.3, R.sub.3, R.sub.6, R.sub.7 and R.sub.8 are H, R.sub.9 is Cl, then R.sub.10 is not 2-Br-phenyl; when R.sub.1, R.sub.2, R.sub.4, R.sub.5, R.sub.1 R.sub.2, R.sub.4 and R.sub.5 are F, R.sub.3, R.sub.3, R.sub.6, R.sub.7, R.sub.8 and R.sub.9 are H, then R.sub.10 is not CF.sub.3.

2. Use of A catalyst for the partial reduction of a carbonyl group in an ester substrate or lactone substrate comprising a compound of general formula (I) according to claim 1 which substrate of said catalyst optionally contains one or more functional group(s) independently selected from the group consisting of non-carbonyl-conjugated olefinic bonds, non-carbonyl-conjugated acetylenic bonds, ether, amide, and halogen groups.

3. The compound according to claim 1, wherein the compound of formula (I) is characterized by general formula (Ia) ##STR00065## wherein X ring and X ring are phenyl groups; R.sub.1 and R.sub.1 are independently selected from the group consisting of H, D and F; R.sub.5 and R.sub.5 are independently selected from the group consisting of H, D and F; each R.sub.2, R.sub.3, R.sub.4, R.sub.2, R.sub.3 and R.sub.4 are independently selected from the group consisting of H, D, F, Cl, Br, alkyl, cycloalkyl and aryl groups, where the alkyl, cycloalkyl and aryl groups are optionally substituted; Y ring is phenyl group; R.sub.6 is selected from the group consisting of H, D and F; R.sub.10 is selected from the group consisting of Cl, Br, I, SF.sub.5, alkyl, cycloalkyl and phenyl groups, where the alkyl, cycloalkyl and phenyl groups are optionally substituted with one or more substituent(s) selected from the following group: alkyl, halogen, hydroxyl and alkoxy, where the alkyl and alkoxy is optionally substituted with halogen); R.sub.7, R.sub.8 and R.sub.9 are independently selected from the group consisting of H, D, F, Cl, Br, alkyl and cycloalkyl groups, where the alkyl and cycloalkyl groups are optionally substituted.

4. The compound according to claim 3, wherein X ring and X ring are phenyl groups, wherein each R.sub.1, R.sub.1, R.sub.5 and R.sub.5 are F; and each R.sub.2, R.sub.3 R.sub.4, R.sub.2, R.sub.3 and R.sub.4 are independently selected from H and F; Y ring is a phenyl group, wherein R.sub.6 is selected from H and F; R.sub.10 is selected from Cl, Br, methyl and pentafluorophenyl groups; and R.sub.7, R.sub.8 and R.sub.9 are independently selected from H and F.

5. The compound according to claim 3, wherein X and X are independently selected from the group consisting of pentafluorophenyl, 2,3,4,6-tetrafluorophenyl, 2,3,5,6-tetrafluorophenyl, 2,4,6-trifluorophenyl, 2,3,6-trifluorophenyl, and 2,6-difluorophenyl groups.

6. The compound according to claim 3, wherein Y is selected from the group consisting of 2-chloro-6-fluorophenyl, 2-bromo-6-fluorophenyl, and perfluoro-1,1-biphen-2-yl groups.

7. The compound according to claim 3, wherein the compound of general formula (I) is selected from the group consisting of the following compounds: (2-bromo-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 1); (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2); (2-bromo-6-fluorophenyl)bis(perfluorophenyl)borane (Compound 3); (perfluoro-[1,1-biphenyl]-2-yl)bis(2,4,6-trifluorophenyl)borane (Compound 4); (2-bromo-6-fluorophenyl)bis(2,4,6-trifluorophenyl)borane (Compound 5); (2-chloro-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 6); and (perfluoro-[1,1-biphenyl]-2-yl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 7); perfluoro-[1,1-biphenyl]-2-yl)bis(2,3,6-trifluorophenyl)borane (Compound 8).

8. The compound according to claim 7, wherein the compound of general formula (I) is selected from the group consisting of the following compounds: (2-bromo-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 1); (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2); (2-bromo-6-fluorophenyl)bis(perfluorophenyl)borane (Compound 3); (perfluoro-[1,1-biphenyl]-2-yl)bis(2,4,6-trifluorophenyl)borane (Compound 4); and (2-chloro-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 6).

9. A method for the preparation of an aldehyde or a lactol by partial reduction of a carbonyl group in an ester substrate or lactone substrate, which substrate optionally contains one or more functional group(s) independently selected from the group consisting of non-carbonyl-conjugated olefinic bonds, non-carbonyl-conjugated acetylenic bonds, ether, amide, and halogen groups, wherein the method comprises the following steps: a) said ester or lactone substrate is reacted with a silane in the presence of a catalytic amount of a compound of formula (I) defined in claim 1 to form a silyl acetal, b) the thus-obtained silyl acetal is hydrolysed with one or more acidic or fluoride containing reagent(s) to form the aldehyde or lactol, and c) optionally the obtained aldehyde or lactol is separated and purified.

10. A compound of general formula (II) ##STR00066## wherein X is a halogen selected from the group consisting of Cl and Br; E is either a (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p, wherein m is an integer from 2 to 12, and n and p are, independently from each other, integers from 1 to 5, and any one of the methylene groups of (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p may be optionally substituted with one or more substituent(s) independently selected from each other from the group consisting of halogens, optionally substituted alkyl groups (preferably methyl or trifluoromethyl groups) or optionally substituted alkoxy groups (preferably methoxy group); R.sub.11 is a trialkylsilyl or dialkylsiloxysilyl group, where the alkyl part is an optionally substituted C.sub.1-6 alkyl group, preferably C.sub.1-4 alkyl group; R.sub.12 is an optionally substituted alkyl group, preferably a C.sub.1-6 alkyl group, preferably C.sub.1-3 alkyl group.

11. The compound of formula (II) according to claim 10, wherein X is a halogen selected from the group consisting of Cl and Br; E is either a (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p, wherein m is an integer from 2 to 10, and n and p are, independently from each other, integers from 1 to 3, and any one of the methylene groups of (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p may be optionally substituted with 1 to 3 substituent(s), independently selected from each other from the group consisting of halogens, optionally substituted alkyl groups (preferably methyl group) or optionally substituted alkoxy groups (preferably methoxy group); R.sub.11 is a trialkylsilyl or dialkylsiloxysilyl group, where the alkyl part is a C.sub.1-2 alkyl group, preferably triethylsilyl or dimethylsiloxysilyl group; R.sub.12 is a C.sub.1-3 alkyl group, preferably methyl, ethyl, propyl or isopropyl group.

12. The compound of formula (II) according to claim 10, which is selected from the group consisting of the following compounds: (4-bromo-1-ethoxybutoxy)triethylsilane (Example 14) (3-bromo-1-ethoxypropoxy)triethylsilane (Example 15) ((5-bromo-1-ethoxypentyl)oxy)triethylsilane (Example 16) ((6-bromo-1-ethoxyhexyl)oxy)triethylsilane (Example 17) (4-bromo-1-isopropoxybutoxy)triethylsilane (Example 18) (2-(2-chloroethoxy)-1-ethoxyethoxy)triethylsilane (Example 19) (2-(2-bromoethoxy)-1-ethoxyethoxy)triethylsilane (Example 21) (4-bromo-1-ethoxy-2-fluorobutoxy)triethylsilane (Example 22) ((4-bromo-1-ethoxypentyl)oxy)triethylsilane (Example 24) (4-bromo-1-ethoxy-2,2-difluorobutoxy)triethylsilane (Example 25) (4-bromo-1-ethoxy-2-methylbutoxy)triethylsilane (Example 26).

13. A compound of general formula (III) ##STR00067## wherein X is a halogen selected from the group consisting of Cl and Br; G is either a (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p, wherein m is an integer from 2 to 12, and n and p are, independently from each other, integers from 1 to 5, and any one of the methylene groups of (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p may be optionally substituted with one or more substituent(s) [e.g. 1 to 5, or 1 to 4, or 1 to 3 or 1 or 2 substituent(s)], independently selected from each other from the group consisting of halogens, optionally substituted alkyl groups (preferably methyl or trifluoromethyl groups) or optionally substituted alkoxy groups (preferably methoxy group); R.sub.13 is an optionally substituted alkyl group, preferably a C.sub.1-36 alkyl group, more preferably methyl group; R.sub.14 is an optionally substituted alkyl group, preferably a C.sub.1-6 alkyl group, preferably C.sub.1-3 alkyl group.

14. The compound of formula (III) according to claim 13, wherein X is a halogen selected from the group consisting of Cl and Br; G is either a (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p, wherein m is an integer from 2 to 10, and n and p are, independently from each other, integers from 1 to 3, and any one of the methylene groups of (CH.sub.2).sub.m or (CH.sub.2).sub.nO(CH.sub.2).sub.p may be optionally substituted with 1 to 3 substituent(s) [e.g. 1 or 2 substituent(s)], independently selected from each other from the group consisting of halogens, optionally substituted alkyl groups (preferably methyl group) or optionally substituted alkoxy groups (preferably methoxy group); R.sub.13 is a C.sub.1-3 alkyl group, preferably methyl group; R.sub.14 is a C.sub.1-3 alkyl group, preferably methyl, ethyl, propyl or isopropyl group.

15. The compound of formula (III) according to claim 13, which is 4,10-bis(3-bromopropyl)-6,6,8,8-tetramethyl-3,5,7,9,11-pentaoxa-6,8-disilatridecane (Example 27).

Description

EXAMPLES

[0166] In Examples 1 to 8 and Example 26, the preparation of those compounds of formula (I) are disclosed which are given in Table 1. The other (reference) compounds of Table 1 were synthetized by analogous processes or were obtained from commercial sources.

Example 1

Synthesis of (2-bromo-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 1, see Entry 12)

[0167] The compound was prepared as described below and illustrated in schemes 3 to 5.

[0168] Step a) Synthesis of (2-bromo-6-fluorophenyl)boronic acid (Compound 1a)

##STR00030##

[0169] In a 500 mL three necked flask, with condenser, nitrogen purge inlet and an inserted digital thermometer, diisopropylamine (8.90 g, 13 mL, 1.1 equiv., 88.0 mmol) was dissolved in tetrahydrofuran (200 mL, abs, N.sub.2 purged) and was cooled to ?78? C. The solution of butyllithium (5.64 g, 35.2 mL, 1.1 equiv., 88.0 mmol, 2.5 M in hexanes) was added dropwise, keeping the reaction temperature below ?60? C. The reaction mixture was stirred for 30 min at ?78? C. Then, 1-bromo-3-fluorobenzene (14.0 g, 8.93 mL, 1 equiv., 80.0 mmol) was added dropwise within 5 min, keeping the reaction temperature under ?70? C. The mixture was stirred for 30 min at ?78? C. Then, trimethyl borate (16.6 g, 18 mL, 2 equiv., 160 mmol) was added dropwise within 10 min and the reaction temperature was maintained below ?70? C. The reaction was then stirred for 30 min at ?78? C., left to warm up to 25? C. and stirred for another 4 h. Afterwards, the reaction mixture was cooled down to 0? C. and 250 mL 1M HCl solution (precooled to 0? C.) was added dropwise, keeping the temperature below 6? C. The reaction was left to warm up to 25? C. and stirred for another 2 h. Then, 160 mL of diethyl ether was added, and the phases were separated.

[0170] The aqueous phase was washed with another 40 mL of diethyl ether. The combined organic phase was washed with 2?160 mL brine and dried using Na.sub.2SO.sub.4. Finally, the solvents were evaporated on a rotary evaporator yielding a crude crystalline product, which can be used for the next synthetic step without further purification.

[0171] Step b) Synthesis of potassium (2-bromo-6-fluorophenyl)trifluoroborate (Compound 1b)

##STR00031##

[0172] In a white 1000 mL polypropylene container, (2-bromo-6-fluorophenyl)boronic acid (Compound 1a) (17.5 g, 1 equiv., 80.0 mmol) was measured in and dissolved in methanol (90 mL, tech). Then, potassium hydrogen fluoride (25.0 g, 4 equiv., 320 mmol) dissolved in water (90 mL) was added in one portion. The resulting suspension was stirred for 16 h. Afterwards, 500 mL of acetone was added and the reaction mixture was stirred for 30 min. The reaction mixture was filtered through filter paper and the solvents were evaporated at 60? C. on a rotary evaporator. Additional 400 mL acetone was added and evaporated again to remove the traces of water. Finally, 100 mL toluene was added and evaporated the same way. The obtained white powder was dissolved once again in 100 mL acetone and filtered through filter paper. The filtrate was evaporated, and the obtained white powder was mixed with 100 mL of hexanes and filtered. The precipitate was washed with 2?50 mL diethyl ether, dried on a rotary evaporator at 60? C. and kept in a vacuum desiccator using P.sub.4O.sub.10 as desiccant. The product is a white, crystalline solid (20.4 g, 72.6 mmol). The combined isolated yield for the first two synthetic steps is 91%.

.SUP.1.H NMR

[0173] .sup.1H NMR (300 MHz, DMSO-d6) ? 7.18 (dq, J=7.8, 0.6 Hz, 1H), 6.99 (td, J=8.0, 6.1 Hz, 1H), 6.85 (dddt, J=9.4, 8.1, 1.2, 0.6 Hz, 1H).

.SUP.19.F NMR

[0174] .sup.19F NMR (282 MHz, DMSO-d6) ? ?96.2 (tdd, J=16.1, 12.6, 6.8 Hz, 1F), ?127.6-?128.6 (m, 3F).

.SUP.13.C NMR

[0175] Partial .sup.13C NMR (75 MHz, Benzene-d6) ? 165.8 (d, J=244.8 Hz, 1C), 128.4 (d, J=3.2 Hz, 1C), 128.4 (d, J=9.6 Hz, 1C), 128.0 (d, J=14.0 Hz, 1C), 113.7 (d, J=27.9 Hz, 1C).

[0176] Step c) Synthesis of (2-bromo-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 1)

##STR00032##

[0177] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, magnesium turnings (1.61 g, 2.3 equiv., 66.3 mmol) were measured in and activated with iodine. Then, 20 mL of abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (5.21 g, 6.04 mL, 2.3 equiv., 66.3 mmol). The solution started to warm up and reflux. 30 mL of diethyl ether was added to dilute the reaction, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 3-bromo-1,2,4,5-tetrafluorobenzene (15.2 g, 8.07 mL, 2.3 equiv., 66.3 mmol) was measured in and dissolved in 90 mL of abs. diethyl ether, after which it was cooled to 0? C. The previously prepared Grignard solution was added dropwise via syringe within 45 min, while keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 500 mL Schlenk flask, potassium (2-bromo-6-fluorophenyl)trifluoroborate (Compound 1b) (8.10 g, 1 equiv., 28.8 mmol) was measured in under N.sub.2, suspended in 20 mL of abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 4? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated at 50? C. in vacuo. Next, 90 mL of abs. toluene was added, and the suspension was sonicated for 10 minutes. The resulting precipitate was filtered off and washed with 2?20 mL of abs. toluene. The combined filtrate was then evaporated at 70? C. in vacuo, resulting an off-white solid. Then, 10 mL of abs. pentane was added, and the resulting suspension was sonicated and filtered to give the product as a white crystalline powder (6.90 g, 14.3 mmol, 50% yield).

.SUP.1.H NMR

[0178] .sup.1H NMR (300 MHz, Benzene-d6) ? 6.98-6.89 (m, 1H), 6.59-6.48 (m, 2H), 6.29-6.15 (m, 2H).

.SUP.19.F NMR

[0179] .sup.19F NMR (282 MHz, Benzene-d6) ? ?102.1-?102.2 (m, 1F), ?129.1-?129.3 (m, 4F), ?138.0-?138.2 (m, 4F).

[0180] .sup.13C NMR

[0181] .sup.13C NMR (75 MHz, Benzene-d6) ? 162.8 (d, J=245.8 Hz, 1C), 148.4 (dddd, J=251.4, 12.8, 8.6, 3.7 Hz, 4C), 146.0 (dm, J=250.2 Hz, 4C), 133.2 (d, J=9.0 Hz, 1C), 132.4-131.5 (m, 1C), 128.3 (d, J=3.2 Hz, 1C), 123.4 (d, J=9.3 Hz, 1C), 120.4-118.8 (m, 2C), 114.1 (d, J=23.2 Hz, 1C), 111.8 (tt, J=22.7, 2.0 Hz, 2C).

Example 2

Synthesis of (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2, see Entry 16)

[0182] The compound was prepared as described below and illustrated in schemes 3, 4 and 6.

[0183] Step a) and Step b) are analogues to EXAMPLE 1.

[0184] Step c) Synthesis Of (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2)

##STR00033##

[0185] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, Magnesium turnings (1.61 g, 2.3 equiv., 66.3 mmol) were measured in and activated with iodine. Then, 20 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (5.21 g, 6.04 mL, 2.3 equiv., 66.3 mmol). The solution started to warm up and reflux. Additional 30 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 2-bromo-1,3,4-trifluorobenzene (14.0 g, 7.85 mL, 2.3 equiv., 66.3 mmol) was measured in and dissolved in 90 mL abs. diethyl ether, after which it was cooled to 0? C. The previously prepared Grignard solution was added dropwise via syringe in 45 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 500 mL Schlenk flask, potassium (2-bromo-6-fluorophenyl)trifluoroborate (Compound 1b) (8.10 g, 1 equiv., 28.8 mmol) was measured in under N.sub.2, suspended in 20 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 4? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated at 50? C. in vacuo. Next, 90 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. The resulting precipitate was filtered off and washed with 2?20 mL abs. toluene. The combined filtrate was then evaporated at 70? C. in vacuo, resulting an off-white solid. Then, 10 mL abs. pentane was added, and the resulting suspension was filtered to yield the product as a white crystalline powder (8.05 g, 18.0 mmol, 63% yield)

.SUP.1.H NMR

[0186] .sup.1H NMR (300 MHz, Benzene-d6) ? 7.04-6.95 (m, 1H), 6.65-6.44 (m, 4H), 6.21-6.11 (m, 2H).

.SUP.19.F NMR

[0187] .sup.19F NMR (282 MHz, Benzene-d6) ? ?102.4-?102.5 (m, 1F), ?103.4-?103.6(m, 2F), ?123.0 (ddt, J=21.9, 9.2, 1.7 Hz, 2F), ?142.6 (dddd, J=21.9, 15.8, 9.4, 3.3 Hz, 2F).

.SUP.13.C NMR

[0188] .sup.13C NMR (75 MHz, Benzene-d6) ? 162.9 (d, J=245.1 Hz, 1C), 160.7 (ddd, J=250.1, 8.5, 2.5 Hz, 2C), 153.0 (ddd, J=254.6, 13.3, 11.4 Hz, 2C), 147.3 (ddd, J=246.0, 14.7, 3.5 Hz, 2C), 133.9-132.4 (m, 1C), 132.5 (d, J=8.9 Hz, 1C), 128.2 (d, J=3.1 Hz, 1C), 123.6 (d, J=9.7 Hz, 1C), 122.9 (ddd, J=19.6, 11.3, 2.5 Hz, 2C), 120.2-118.9 (m, 2C), 113.9 (d, J=23.3 Hz, 1C), 111.5 (ddd, J=27.5, 5.8, 4.1 Hz, 2C).

Example 3

Synthesis of (2-bromo-6-fluorophenyl)bis(perfluorophenyl)borane (Compound 3, See Entry 11).

[0189] The compound was prepared as described below and illustrated in schemes 3, 4 and 7.

[0190] Step a) and Step b) are analogues to EXAMPLE 1.

Step c) Synthesis of (2-bromo-6-fluorophenyl)bis(perfluorophenyl)borane (Compound 3)

##STR00034##

[0191] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, Magnesium turnings (1.61 g, 2.3 equiv., 66.3 mmol) were measured in and activated with iodine. Then, 20 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (5.21 g, 6.04 mL, 2.3 equiv., 66.3 mmol). The solution started to warm up and reflux. Additional 30 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 1-bromo-2,3,4,5,6-pentafluorobenzene (16.4 g, 8.27 mL, 2.3 equiv., 66.3 mmol) was measured in and dissolved in 90 mL abs. diethyl ether, after which it was cooled to 0? C. The previously prepared Grignard solution was added dropwise via syringe in 45 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 500 mL Schlenk flask, potassium (2-bromo-6-fluorophenyl)trifluoroborate (Compound 1b) (8.10 g, 1 equiv., 28.8 mmol) was measured in under N.sub.2 suspended in 20 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 4? C. The reaction mixture was left to warm up to 25? C. and stirred for an additional 18 h. Afterwards, the solvent was evaporated at 50? C. in vacuo. Next, 90 mL abs. toluene was added and the suspension was sonicated for 10 minutes. The resulting precipitate was filtered off and washed with 2?20 mL abs. toluene. The combined filtrate was then evaporated at 70? C. in vacuo, resulting an off-white solid. Then, 10 mL abs. pentane was added, and the resulting suspension was filtered to yield the product as a white crystalline powder (5.08 g, 9.79 mmol, 34% yield).

.SUP.1.H NMR

[0192] .sup.1H NMR (300 MHz, Benzene-d6) ? 6.99-6.91 (m, 1H), 6.64-6.55 (m, 2H).

.SUP.19.F NMR

[0193] .sup.19F NMR (282 MHz, Benzene-d6) ? ?102.4-?102.5 (m, 1F), ?127.9-?128.1 (m, 4F), ?142.9 (tt, J=20.9, 7.0 Hz, 2F), ?160.6-?160.87 (m, 4F).

.SUP.13.C NMR

[0194] .sup.13C NMR (75 MHz, Benzene-d6) ? 162.7 (d, J=245.4 Hz, 1C), 149.2 (dtt, J=252.6, 10.9, 4.2 Hz, 4C), 145.2 (dm, J=261.8 Hz, 2C), 137.7 (dm, J=256.1 Hz, 4C), 133.2 (d, J=9.1 Hz, 1C), 132.4-131.3 (m, 1C), 128.3 (d, J=3.1 Hz, 1C), 123.2 (d, J=9.4 Hz, 1C), 114.1 (d, J=23.1 Hz, 1C), 114.3-112.9 (m, 2C).

Example 4

Synthesis of (perfluoro-[1,1-biphenyl]-2-yl)bis(2,4,6-trifluorophenyl)borane (Compound 4, See Entry 15)

[0195] The compound was prepared as described below and illustrated in schemes 8-10.

Step a) Synthesis of (perfluoro-[1,1-biphenyl]-2-yl)boronic acid (Compound 4a, Pfp=C.sub.6F.sub.5)

##STR00035##

[0196] Preparation of i-PrMgCl: A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, magnesium turnings (1.89 g, 1.0 equiv., 77.7 mmol) were measured in and 45 mL abs. diethyl ether was added. Then 2-chloropropane (6.11 g, 7.11 mL, 1.0 equiv., 77.7 mmol) was added dropwise. The solution started to warm up and reflux. The dropwise addition of 2-chloropropane was continued to maintain the reflux.

[0197] In a 500 mL three necked flask, with condenser, nitrogen purge inlet and an inserted digital thermometer, 2-bromo-2,3,3,4,4,5,5,6,6-nonafluoro-1,1-biphenyl (30.7 g, 1.0 equiv., 77.7 mmol) was dissolved in diethyl ether (50 mL, abs, N.sub.2 purged) and cooled to 0? C. with an ice bath. The solution of i-PrMgCl was added dropwise, keeping the reaction temperature between 0 and 5? C. Then the reaction mixture was stirred for 60 minutes at 25? C. Then, trimethyl borate (16.2 g, 17.7 mL, 2.0 equiv., 155 mmol) was added dropwise within 30 min, keeping the reaction temperature at 0? C. The mixture was stirred for an additional 16 hours at 25? C. Afterwards, the reaction was cooled down to 0? C. and 80 mL 1M HCl solution (precooled to 0? C.) was added dropwise, keeping the temperature below 5? C. The reaction was left to warm up to 25? C. and stirred for another 2 h. Then, 200 mL diethyl ether was added, and the phases were separated. The aqueous phase was washed with another 50 mL diethyl ether. The combined organic phase was washed with 2?160 mL brine and dried using Na.sub.2SO.sub.4. Finally, the solvents were evaporated on a rotary evaporator yielding a crude product, which can be used for the next synthetic step without further purification.

Step b) Synthesis of potassium trifluoro(perfluoro-[1,1-biphenyl]-2-yl)borate (Compound 4b)

##STR00036##

[0198] In a white 1000 mL polypropylene container, (perfluoro-[1,1-biphenyl]-2-yl)boronic acid (26.59 g, 77.7 mmol) was measured in and dissolved in methanol (78 mL, tech). Then, potassium hydrogen fluoride (24.30 g, 4,0 equiv., 311.11 mmol) dissolved in distilled water (78 mL) was added in one portion. The resulting suspension was stirred for 16 h. Afterwards, 500 mL acetone was added. The reaction mixture was filtered through filter paper, and the solvents were evaporated at 60? C. on a rotary evaporator. Additional 400 mL acetone was added and evaporated again to remove the traces of water. Then, 100 mL toluene was added and evaporated the same way. The obtained white powder was dissolved once again in 100 mL acetone and filtered through filter paper. The solvent was evaporated on a rotary evaporator, and the obtained white powder was mixed with 100 mL of hexanes, filtered, then dried at 60? C. The product is a white, crystalline solid (25.73 g, 63.68 mmol). The isolated yield for this synthetic step is 81.9%. equiv.

.SUP.19.F NMR

[0199] .sup.19F NMR (282 MHz, DMSO-d6) ? ?132.5-?132.8 (m, 1F), ?134.0-?134.74 (m, 3F), ?139.9-?140.1 (m, 2F), ?141.0 (dd, J=22.5, 13.8 Hz, 1F), ?155.8 (t, J=22.1 Hz, 1F), ?156.0 (dd, J=25.2, 20.9 Hz, 1F), ?160.9 (ddd, J=22.9, 20.9, 2.7 Hz, 1F), ?164.4-?164.68 (m, 2F).

.SUP.13.C NMR

[0200] Partial .sup.13C NMR (75 MHz, DMSO-d6) ? 148.7 (d, J=240.7 Hz, 1C), 144.2 (dm, J=244.8 Hz, 2C), 143.7 (dm, J=243.2 Hz, 1C), 140.0 (dm, J=255.6 Hz, 1C), 137.6 (dm, J=245.9 Hz, 1C), 136.4 (dm, J=249.1 Hz, 2C).

Step c) Synthesis of (2-bromo-6-fluorophenyl)bis(2,4,6-trifluorophenyl)borane (Compound 4)

##STR00037##

[0201] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, magnesium turnings (280 mg, 2.3 equiv., 11.5 mmol) were measured in. Then, 10 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (903 mg, 1.05 mL, 2.3 equiv., 11.5 mmol). The solution started to warm up and reflux. Additional 10 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 100 mL 2-necked flask, 2-bromo-1,3,5-trifluorobenzene (2.43 g, 1.355 mL, 2.3 equiv., 11.5 mmol) was measured in and dissolved in 40 mL abs. diethyl ether, after which the solution was cooled to 0? C. The previously prepared i-PrMgCl solution was added dropwise via syringe within 20 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 100 mL Schlenk flask, potassium trifluoro(perfluoro-[1,1-biphenyl]-2-yl)borate (Compound 4b) (2.11 g, 1 equiv., 5.00 mmol) was measured in under N.sub.2, suspended in 5 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 5? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated in vacuo. Next, 10 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. The resulting precipitate was filtered off and washed with 2?5 mL abs. toluene. The combined filtrate was then evaporated at 45? C. in vacuo, resulting an off-white solid. Then, 10 mL abs. pentane was added, and the resulting suspension was filtered to yield the product as an off white crystalline powder (1.33 g, 2.27 mmol, 45% yield).

.SUP.1.H NMR

[0202] .sup.1H NMR (300 MHz, Benzene-d6) ? 6.02-5.91 (m, 4H).

.SUP.19.F NMR

[0203] .sup.19F NMR (282 MHz, Benzene-d6) ? ?94.2 (ddt, J=12.4, 8.4, 4.1 Hz, 4F), ?97.0-?97.2 (m, 2F), ?129.0 (ddd, J=22.8, 12.2, 6.6 Hz, 1F), ?136.5-?136.8 (m, 1F), ?139.4-?139.7 (m, 2F), ?148.63 (td, J=20.7, 6.7 Hz, 1F), ?151.8-?152.0 (m, 1F), ?152.9 (ddd, J=22.9, 20.2, 5.8 Hz, 1F), ?161.9-?162.2 (m, 2F).

.SUP.13.C NMR

[0204] Partial .sup.13C NMR (75 MHz, Benzene-d6) ? 167.6 (dt,J=258.3, 16.9 Hz, 2C), 166.6 (ddd, J=254.7, 15.3, 13.7 Hz, 4C), 149.1 (dm, J=246.4 Hz, 1C), 146.4 (ddd, J=251.2, 10.9, 3.5 Hz, 1C), 144.4 (dddt, J=249.2, 10.6, 7.0, 4.0 Hz, 2C), 142.7 (dddd, J=259.3, 17.3, 12.5, 4.9 Hz, 1C), 141.7 (dm, J=256.6 Hz, 2C), 137.7 (dm, J=254.7 Hz, 2C), 114.5-113.4 (m, 2C), 113.2-112.7 (m, 1C), 108.9-108.2 (m, 1C), 100.6 (ddd, J=28.9, 25.0, 3.6 Hz, 4C).

Example 5

Synthesis of (2-bromo-6-fluorophenyl)bis(2,4,6-trifluorophenyl)borane (Compound 5, See Entry 19)

[0205] The compound was prepared as described below and illustrated in schemes 3, 4 and 11.

[0206] Step a) and Step b) are analogues to EXAMPLE 1.

Step c) Synthesis of (2-bromo-6-fluorophenyl)bis(2,4,6-trifluorophenyl)borane (Compound 5)

##STR00038##

[0207] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, Magnesium turnings (1.61 g, 2.3 equiv., 66.3 mmol) were measured in and activated with iodine. Then, 20 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (5.21 g, 6.04 mL, 2.3 equiv., 66.3 mmol). The solution started to warm up and reflux. Additional 30 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 2-bromo-1,3,5-trifluorobenzene (14.0 g, 7.82 mL, 2.3 equiv., 66.3 mmol) was measured in and dissolved in 90 mL abs. diethyl ether, after which it was cooled to 0? C. The previously prepared Grignard solution was added dropwise via syringe in 45 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 500 mL Schlenk flask, potassium (2-bromo-6-fluorophenyl)trifluoroborate (Compound 1b) (8.10 g, 1 equiv., 28.8 mmol) was measured in under N.sub.2 suspended in 20 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 4? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated at 50? C. in vacuo. Next, 90 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. with the resulting precipitate was filtered off and washed with 2?20 mL abs. toluene. The combined filtrate was then evaporated at 70? C. in vacuo, resulting an off-white solid. Then, 10 mL abs. pentane was added, and the resulting suspension was filtered to yield the product as a white crystalline powder (6.05 g, 13.5 mmol, 47% yield).

.SUP.1.H NMR

[0208] .sup.1H NMR (500 MHz, Benzene-d6) ? 7.04 (dd, J=7.5, 1.3 Hz, 1H), 6.68-6.60 (m, 2H), 6.14-6.07 (m, 4H).

.SUP.19.F NMR

[0209] .sup.19F NMR (282 MHz, Benzene-d6) ? ?94.4 (td, J=9.8, 2.1 Hz, 4F), ?98.7 (tt, J=11.5, 8.8 Hz, 2F), ?102.8-?102.9 (m, 1F).

.SUP.13.C NMR

[0210] .sup.13C NMR (126 MHz, Benzene-d6) ? 167.4 (dt, J=256.6, 16.9 Hz, 2C), 167.1 (ddd, J=254.8, 15.4, 13.6 Hz, 4C), 162.8 (d, J=244.4 Hz, 1C), 134.2-133.5 (m, 1C), 132.0 (d, J=8.7 Hz, 1C), 128.1 (d, J=3.0 Hz, 1C), 123.7 (d, J=10.0 Hz, 1C), 114.9-114.1 (m, 2C), 113.8 (d, J=23.5 Hz, 1C), 100.6 (ddd, J=30.1, 24.9, 3.2 Hz, 4C)

Example 6

Synthesis of (2-chloro-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 6, See Entry 10)

[0211] The compound was prepared as described below and illustrated in schemes 12 to 14.

Step a) Synthesis of (2-chloro-6-fluorophenyl)boronic acid (Compound 6a)

##STR00039##

[0212] In a 500 mL necked flask, with condenser, nitrogen purge inlet and an inserted digital thermometer, at ?75? C., 1-chloro-3-fluorobenzene (15.7 mL, 19.142 g, 146.6 mmol) was added to a solution of butyllithium (161.3 mmol) in tetrahydrofuran (117 mL, abs) and hexanes (66 mL, abs). The reaction mixture was stirred for 2 hours at ?78? C. Then, trimethyl borate (30.47 g, 32.7 mL, 2 equiv., 40.0 mmol) was added dropwise within 50 min and the reaction temperature was maintained below ?71? C. The reaction was left to warm up to 25? C. and then stirred for 16 hours. Afterwards, the reaction was cooled down to 0? C. and 35 mL 1M HCl solution (precooled to 0? C.) was added dropwise, keeping the temperature below 6? C. The reaction was left to warm up to 25? C. and stirred for another 2 h. Then, the phases were separated. The aqueous phase was washed with another 30 mL diethyl ether. The combined organic phase was washed with 2?30 mL brine and dried using Na.sub.2SO.sub.4. Finally, the solvents were evaporated on a rotary evaporator yielding a nearly solid, which was washed with hexane and dried. The product was obtained as a white powder (20.76 g, 119.06 mmol). The yield of this synthetic step is 81%. The crude product can be used for the next synthetic step without further purification.

Step b) Synthesis of potassium (2-chloro-6-fluorophenyl)trifluoroborate (Compound 6b)

##STR00040##

[0213] In a white 1000 mL polypropylene container, (2-chloro-6-fluorophenyl)boronic acid (Compound 6a) (20.76 g, 1 equiv., 119.06 mmol) was measured in and dissolved in methanol (325 mL, tech). Then, potassium hydrogen fluoride (37.2 g, 4 equiv., 476.22 mmol) dissolved in water (325 mL) was added in one portion. The resulting suspension was stirred for 16 h.

[0214] Afterwards, 300 mL acetone was added, and the reaction mixture was stirred for 30 min. The reaction mixture was filtered through filter paper and the solvents were evaporated at 60? C. on a rotary evaporator. Additional 2?30 mL acetone was added and evaporated again to remove the traces of water. Finally, 50 mL toluene was added and evaporated the same way. The obtained white powder was dissolved once again in 100 mL acetone and filtered through filter paper. The solvent was evaporated on a rotary evaporator, and the obtained white powder was mixed with 100 mL hexanes and filtered. The filtride was dried on a rotary evaporator at 60? C. and kept in a vacuum desiccator using P.sub.4O.sub.10 as desiccant. The product is a white, crystalline solid (27.00 g, 114.19 mmol). The isolated yield for this synthetic step is 96%.

.SUP.1.H NMR

[0215] .sup.1H NMR (500 MHz, DMSO-d6) ? 7.09 (td, J=8.0, 6.2 Hz, 1H), 7.00 (d, J=7.8 Hz, 1H), 6.82 (t, J=8.7 Hz, 1H).

.SUP.19.F NMR

[0216] .sup.19F NMR (282 MHz, DMSO-d6) ? ?102.2- ?102.5 (m, 1F), ?132.2-?132.9 (m, 3F).

.SUP.13.C NMR

[0217] .sup.13C NMR (126 MHz, DMSO-d6) ? 166.0 (d, J=243.0 Hz, 1C), 138.9 (d, J=14.8 Hz, 1C), 134.2-131.3 (m, 1C), 128.0 (d, J=10.0 Hz, 1C), 125.0 (d, J=3.4 Hz, 1C), 113.2 (d, J=27.9 Hz, 1C).

Step c) Synthesis of (2-chloro-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 6)

##STR00041##

[0218] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, Magnesium turnings (763 mg, 2.3 equiv., 31.4 mmol) were measured in and activated with iodine. Then, 18 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (2.47 g, 2.90 mL, 2.3 equiv., 31.4 mmol). The solution started to warm up and reflux. Additional 30 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 3-bromo-1,2,4,5-tetrafluorobenzene (7.19 g, 2.3 equiv., 31.4 mmol) was measured in and dissolved in 95 mL abs. diethyl ether, after which the solution was cooled to 0? C. The previously prepared Grignard solution was added dropwise via syringe within 25 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 250 mL Schlenk flask, potassium (2-chloro-6-fluorophenyl)trifluoroborate (Compound 6b) (3.84 g, 1 equiv., 13.65 mmol) was measured in under N.sub.2 suspended in 12 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 4? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated at 50? C. in vacuo. Next, 60 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. with the resulting precipitate was filtered off and washed with 2?10 mL abs. toluene. The combined filtrate was then evaporated at 70? C. invacuo, resulting an off-white solid. Then, 2?5 mL abs. pentane was added, and the resulting suspension was filtered to yield the product as a white crystalline powder (2.15 g, 4.89 mmol, 36% yield).

.SUP.1.H NMR

[0219] .sup.1H NMR (300 MHz, Benzene-d6) ? 6.77 (dt, J=8.0, 0.9 Hz, 1H), 6.62 (tdd, J=8.1, 6.4, 0.7 Hz, 1H), 6.51 (tt, J=8.4, 0.9 Hz, 1H), 6.25 (ttd, J=9.3, 7.5, 0.7 Hz, 2H).

.SUP.19.F NMR

[0220] .sup.19F NMR (282 MHz, Benzene-d6) ? ?101.8-?101.9 (m, 1F), ?129.5-?129.7 (m, 4F), ?138.0-?138.2 (m, 4F).

.SUP.13.C NMR

[0221] .sup.13C NMR (75 MHz, Benzene-d6) ? 163.3 (d, J=246.1 Hz, 1C), 148.2 (dddd, J=250.8, 12.7, 8.7, 3.6 Hz, 4C), 146.1 (dm, J=250.3 Hz, 4C), 136.1 (d, J=9.9 Hz, 1C), 133.5 (d, J=9.6 Hz, 1C), 130.2 -128.8 (m, 1C), 125.5 (d, J=3.1 Hz, 1C), 120.6-119.2 (m, 2C), 113.8 (d, J=23.4 Hz. 1C), 111.6 (tt, J=22.7, 2.0 Hz, 2C).

Example 7

Synthesis of (perfluoro-[1,1-biphenyl]-2-yl)bis(2,3,5,6-Tetrafluorophenyl)borane (Compound 7, See Entry 18)

[0222] The compound was prepared as described below and illustrated in schemes 8, 9 and 15.

[0223] Step a) and Step b) are analogues to EXAMPLE 4.

Step c) Synthesis of (perfluoro-[1,1-Biphenyl]-2-yl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 7)

##STR00042##

[0224] A 100 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, magnesium turnings (671 mg, 2.3 equiv., 27.6 mmol) were measured in and activated with iodine. Then, 20 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (2.17 g, 2.52 mL, 2.3 equiv., 27.6 mmol). The solution started to warm up and reflux. Additional 30 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 3-bromo-1,2,4,5-tetrafluorobenzene (6.32 g, 3.36 mL, 2.3 equiv., 27.6 mmol) was measured in and dissolved in 40 mL abs. diethyl ether, after which it was cooled to 0? C. The previously prepared i-PrMgCl solution was added dropwise via syringe within 25 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 250 mL Schlenk flask, potassium trifluoro(perfluoro-[1,1-biphenyl]-2-yl)borate (Compound 4b) (5.10 g, 1 equiv., 12.0 mmol) was measured in under N.sub.2 suspended in 15 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 5? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated in vacuo. Next, 20 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. The resulting precipitate was filtered off and washed with 2?15 mL abs. toluene. The combined filtrate was then evaporated at 45? C. in vacuo, resulting an off-white solid. Then, 20 mL abs. pentane was added, and the suspension was sonicated for 25 minutes. The resulting suspension was filtered to yield the product as an off-white crystalline powder (3.26 g, 5.22 mmol, 44% yield).

.SUP.1.H NMR

[0225] .sup.1H NMR (300 MHz, Benzene-d6) ? 6.15 (tt,J=9.3, 7.6 Hz, 2H).

.SUP.19.F NMR

[0226] .sup.19F NMR (282 MHz, Benzene-d6) ? ?127.7 (ddd, J=22.9, 11.6, 7.5 Hz, 1F), ?129.6 (bs, 4F), ?135.4 (ddq, J=23.3, 11.7, 5.8 Hz, 1F), ?137.7-?138.0 (m, 4F), ?139.1-?139.4 (m, 2F), ?146.4 (bs, 1F), ?151.1 (t, J=21.0 Hz, 1F), ?151.9 (td, J=21.5, 5.9 Hz, 1F), ?161.3-?161.5 (m, 2F).

.SUP.13.C NMR

[0227] .sup.13C NMR (126 MHz, Benzene-d6)? 149.9 (dd, J=246.8, 9.8 Hz, 1C), 147.7 (dddd, J=249.5, 12.9, 8.7, 3.6 Hz, 4C), 146.5 (dd, J=251.3, 11.3 Hz, 1C), 146.0 (dddd, J=251.6, 16.3, 8.9, 3.6 Hz, 4C), 144.5 (dm, J=248.4 Hz, 2C), 143.2 (dm, J=261.0 Hz, 1C), 142.0 (dtt, J=258.0, 13.2, 4.8 Hz, 1C), 141.5 (dddd, J=260.1, 19.6, 12.1, 3.3 Hz, 1C), 137.7 (dddd, J=253.1, 16.4, 12.4, 4.0 Hz, 2C), 126.5 (d, J=20.1 Hz, 1C), 119.7 (t, J=21.5 Hz, 2C), 113.7-113.4 (m, 1C), 111.1 (t, J=10 22.6 Hz, 2C), 108.1 (t, J=18.5 Hz, 1C).

Example 8

Synthesis of (perfluoro-[1,1-biphenyl]-2-yl)bis(2,3,6-trifluorophenyl)borane (Compound 8, See Entry 17)

[0228] The compound was prepared as described below and illustrated in schemes 8, 9 and 16.

[0229] Step a) and Step b) are analogues to EXAMPLE 4.

Step c) Synthesis of (perfluoro-[1,1-biphenyl]-2-yl)bis(2,3,6-trifluorophenyl)borane (Compound 8)

##STR00043##

[0230] A 100 mL 3-necked flask was equipped with a reflux condenser and N2 inlet, magnesium turnings (648 mg, 2.5 equiv., 25.66 mmol) were measured in and activated with iodine. Then, 25 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (2.09 g, 2.43 mL, 2.5 equiv., 25.66 mmol). The solution started to warm up and reflux. Additional 30 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 2-bromo-1,3,4-trifluorobenzene (5.62 g, 3.15 mL, 2.5 equiv., 25.66 mmol) was measured in and dissolved in 40 mL abs. diethyl ether, after which it was cooled to 0? C. The previously prepared i-PrMgCl solution was added dropwise via syringe within 25 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 250 mL Schlenk flask, potassium trifluoro(perfluoro-[1,1-biphenyl]-2-yl)borate (4.50 g, 1 equiv., 10.66 mmol) was measured in under N.sub.2, suspended in 10 mL abs. diethyl ether and cooled down to 0? C. The cool (0? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under 5 ? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18 h. Afterwards, the solvent was evaporated in vacuo. Next, 20 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. The resulting precipitate was filtered off and washed with 2?15 mL abs. toluene. The combined filtrate was then evaporated at 45? C. in vacuo, resulting an off-white solid. Then, 20 mL abs. pentane was added, and the suspension was sonicated for 25 minutes. The resulting suspension was filtered to yield the product as a white crystalline powder (1.883 g, 3.202 mmol, 30% yield).

.SUP.1.H NMR

[0231] .sup.1H NMR (500 MHz, Benzene-d6) ? 6.36 (qd, J=9.2, 5.2 Hz, 2H), 5.99 (tdd, J=8.9, 3.3, 1.8 Hz, 2H).

.SUP.19.F NMR

[0232] .sup.19F NMR (282 MHz, Benzene-d6) ? -103.3 (2F), ?122.59 (d, J=21.7 Hz, 2F), ?127.77 (ddd, J=22.8, 12.1, 7.4 Hz, 1F), ?135.96 (ddd, J=22.2, 12.0, 6.0 Hz, 1F), ?139.4 (d, J=22.5 Hz, 2F), ?142.1 (dddd, J=21.6, 15.7, 9.4, 3.3 Hz, 2F), ?146.6 (d, J=22.8 Hz, 1F), ?151.56 (t, J=21.3 Hz, 1F), ?152.0 (ddd, J=22.9, 20.5, 5.9 Hz, 1F), ?161.5-?161.72 (m, 2F).

.SUP.13 .C NMR

[0233] Partial .sup.13C NMR (126 MHz, Benzene-d6,) ? 160.0 (ddd, J=249.9, 8.2, 2.6 Hz, 2C), 152.3 (ddd, J=254.5, 13.6, 11.1 Hz, 2C), 149.5 (dd, J=247.4, 9.7 Hz, 1C), 147.1 (ddd, J=247.4, 14.6, 3.6 Hz, 2C), 146.4 (dd, J=252.1, 11.7 Hz, 1C), 144.5 (dm, J=249.3 Hz, 2C), 143.3 (dm, J=260.7 Hz, 1C), 141.8 (dm, J=258.2 Hz, 1C), 141.5 (dm, J=259.3 Hz, 1C), 137.6 (dm, J=255.1 Hz, 2C), 123.2 (dd, J=19.4, 11.2 Hz, 2C), 119.4-118.6 (m, 2C), 113.6-113.0 (m, 1C), 111.5 (ddd, J=27.4, 5.9, 3.9 Hz, 2C), 108.3 (t, J=15.9 Hz, 1C).

Example 9

Reduction of Tung Oil

[0234] The major fatty acid component of tung oil is alpha-eleostearic acid (82%) containing 1 cis and 2 trans double bonds, all in conjugation. The isomerization and overreduction of these double bonds can be avoided be reducing the triglyceride directly through hydrosilylation using the BrF(F.sub.3a).sub.2 borane (Compound 2) as catalyst.

##STR00044##

[0235] In an oven dried 4 mL vial the ester, propane-1,2,3-triyl (9Z,9Z,9Z,11E,11E,11E,13E,13E,13E)-tris(octadeca-9,11,13-trienoate) (146 mg, 0.33 equiv., 0.166 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6[(2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (2.26 mg, 100 ?L, 0.05 M in benzene-d6, 0.01 equiv., 5.0 ?mol)] was added at room temperature. Then, under stirring, triethylsilane (64.4 mg, 89 ?L, 1.1 equiv., 0.55 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by .sup.1H NMR through the complete disappearance of the original glyceridic CH.sub.2 peaks ((Benzene-d6) ? 4.29 (dd, J=11.9, 4.1 Hz, 2H), 4.07 (dd, J=11.9, 6.0 Hz, 2H)) and the appearance of the acetalic CH peak ((Benzene-d6) ? 5.03-4.93 (m, 2H)).

[0236] 3,3,13,13-Tetraethyl-5,11-di((8Z,10E,12E)-heptadeca-8,10,12-trien-1-yl) -8-(((9Z,11E,13E)-1-((triethylsilyl)oxy)octadeca-9,11,13-trien-1-yl)oxy)-4,6,10,12-tetraoxa-3,13-disilapentadecane:

[0237] .sup.1H NMR (500 MHz, Benzene-d6) ? 6.56 (dd, J=14.6, 11.3 Hz, 3H), 6.29-6.11 (m, 9H), 5.63 (dt, J=14.5, 7.1 Hz, 3H), 5.52-5.43 (m, 3H), 5.39-5.28 (m, 1H), 5.03-4.93 (m, 2H), 4.26-3.63 (m, 5H), 2.26-1.99 (m, 10H), 1.94-1.51 (m, 12H), 1.46-1.21 (m, 38H), 1.17-0.68 (m, 54H).

[0238] Next, the silyl acetal was hydrolysed by diluting the reaction mixture with 5 mL of THF and adding aqueous hydrochloric acid (182 mg, 5.0 mL, 1 M, 10 equiv., 5.0 mmol) to it. After 16 hours, the reaction mixture was extracted with 30 mL ethyl-acetate, washed with 30 mL saturated NaHCO.sub.3 solution, dried over MgSO 4 and the solvent was removed under reduced pressure. The resulting oil contained alpha-eleostearaldehyde as a major constituent (>65 m/m %) and also minor contaminants from glycerol (<5 m/m %), hexaethyldisiloxane (<25 m/m %) and the other fatty acid components of tung oil (<5 m/m %) based on 1 HNMR. The aldehydic proton is clearly visible at ?9.33 (t, J=1.7 Hz, 1H), while the peaks of the silyl-acetal disappeared completely, indicating total conversion. The double bonds remained intact throughout the process as indicated by the olefinic H peaks ((Benzene-d6) ? 6.53 (dd, J=14.7, 11.2 Hz, 1H), 6.30-6.09 (m, 3H), 5.61 (dt, J=14.5, 7.1 Hz, 1H), 5.40 (dt, J=10.9, 7.7 Hz, 1H)).

[0239] (9Z,11E,13E)-Octadeca-9,11,13-trienal:

[0240] .sup.1H NMR (500 MHz, Benzene-d6) ? 9.33 (t, J=1.8 Hz, 1H), 6.53 (dd, J=14.7, 11.2 Hz, 1H), 6.30-6.09 (m, 3H), 5.61 (dt,J=14.5, 7.1 Hz, 1H), 5.40 (dt, J=10.9, 7.7 Hz, 1H), 2.15 (qd, J=7.5, 1.5 Hz, 2H), 2.04-1.99 (m, 2H), 1.88-1.82 (m, 2H), 1.36-0.95 (m, 14H), 0.85 (t, J=7.1 Hz, 3H).

Example 10

Reduction of Jojoba Oil

[0241] Jojoba oil is composed almost entirely of mono-esters (wax esters). Its major fatty acid component is 11-eicosenoic acid, containing 1 double bond, and the major alcoholic components is 11-eicosanol.

##STR00045##

[0242] In an oven dried 4 mL vial the ester, icos-11-en-1-yl icos-11-enoate (295 mg, 1 equiv., 0.500 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 [(2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (2.23 mg, 100 ?L, 0.05 M in benzene-d6, 0.01 equiv., 5.00 ?mol)] was added at room temperature. Then, under stirring, triethylsilane (64.0 mg, 87.8 ?L, 1.1 equiv., 550 ?mol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by .sup.1H NMR.

[0243] Triethyl((1-(icos-11-en-1-yloxy)icos-11-en-1-yl)oxy)silane: .sup.1H NMR (500 MHz, Benzene-d6) ? 5.51 (ddt, J=5.9, 4.4, 1.7 Hz, 4H), 4.90 (dd, J=6.0, 4.4 Hz, 1H), 3.75 (dtd, J=8.2, 6.5, 1.5 Hz, 1H), 3.41 (dtd, J=7.9, 6.5, 1.3 Hz, 1H), 2.12 (tdd, J=7.4, 5.5, 2.5 Hz, 8H), 1.89-1.23 (m, 56H), 1.08 (t, J=7.9 Hz, 9H), 0.92 (t,J=6.8 Hz, 6H), 0.71 (q, J=8.0 Hz, 6H).

[0244] Next, the silyl-acetal was hydrolysed by diluting the reaction mixture with 5 mL of THF and adding aqueous hydrochloric acid (182 mg, 5.0 mL, 1 M, 10 equiv., 5.0 mmol) to it. After 16 hours, the reaction mixture was extracted with 30 mL ethyl-acetate, washed with 30 mL saturated NaHCO.sub.3 solution, dried over MgSO.sub.4 and the solvent was removed under reduced pressure. The resulting oil contained icos-11-enal as a major constituent (>55 m/m %) and also minor contaminants from 11-eicosanol (<40 m/m %) and hexaethyldisiloxane (<5 m/m %) based on .sup.1H NMR. The aldehydic proton is clearly visible at ? 9.35 (t, J=1.8 Hz, 1H), while the peaks of the silyl-acetal disappeared completely, indicating total conversion. The double bonds remained intact throughout the process as indicated by the olefinic H peaks (Benzene-d6) ? 5.48 (t, J=5.0 Hz, 2H).

[0245] Icos-11-enal: .sup.1H NMR (500 MHz, Benzene-d6) ? 9.35 (t, J=1.8 Hz, 1H), 5.48 (t, J=5.0 Hz, 2H), 2.09 (q, J=6.6 Hz, 4H), 1.85 (td, J=7.3, 1.9 Hz, 2H), 1.45 1.04 (m, 26H), 0.90 (t, J=6.8 Hz, 3H).

Example 11

Reduction of Ethyl 2,2,2-trifluoroacetate

[0246] 2,2,2-trifluoroacetaldehyde is an important synthetic building block in medicinal chemistry. The synthesis and usage of this compound on the other hand is cumbersome due to its low boiling point (20? C.). The use of its silyl-acetal as a synthetic precursor could become a viable alternative.

[0247] The silyl-acetal can be synthesized starting from the widely available ethyl 2,2,2-trifluoroacetate, but due to the low Lewis basicity of this ester, a stronger Lewis acid is needed, like the F.sub.9(F.sub.4), borane (Compound 7).

##STR00046##

[0248] In an oven dried 4 mL vial the ester, ethyl 2,2,2-trifluoroacetate (71.0 mg, 59.5 ?L, 1 equiv., 0.500 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (perfluoro-[1,1-biphenyl]-2-yl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 7, Entry 18) (2.68 mg, 100 ?L, 0.05 M in benzene-d6, 0.01 equiv., 5.00 ?mol) was added at room temperature. Then, under stirring, triethylsilane (116 mg, 160 ?L, 2 equiv., 1.00 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by .sup.1H NMR.

Product: (1-ethoxy-2,2,2-trifluoroethoxy)triethylsilane (90% NMR yield)

.SUP.1.H NMR

[0249] Partial .sup.1H NMR (500 MHz, Benzene-d6) ? 4.78 (q, J=3.8 Hz, 1H), 3.53-3.45 (m, 1H), 3.30-3.37 (m, 1H).

Example 12

Reduction of ?-Butyrolactone

[0250] The selective reduction of lactones into lactols is a difficult synthetic problem often encountered during the syntheses of some important pharmaceutical intermediates. This is also the case in the synthesis of prostaglandins, where the reduction of a y-butyrolactone moiety is a challenging task. The problem of overreduction in the case of lactones is even more pronounced, so a weaker Lewis acid is needed. This concept is demonstrated in this example, where we used a borane having weaker Lewis acidity, the BrF(F.sub.3s).sub.2 borane (Compound 5), to reduce ?-butyrolactone with high selectivity.

##STR00047##

[0251] In an oven dried 4 mL vial the lactone, dihydrofuran-2(3H)-one (86 mg, 76 ?L, 1 equiv., 1.0 mmol) was measured in under nitrogen, and dissolved in 0.8 ml benzene-d6. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,4,6-trifluorophenyl)borane (Compound 5, Entry 19) (4.4 mg, 0.20 mL, 0.05 M in benzene-d6, 0.01 equiv., 10 ?mol) was added at room temperature. Then, under stirring, triethylsilane (0.14 g, 0.19 mL, 1.2 equiv., 1.2 mmol) was added dropwise to the reaction mixture. The reaction was stirred for a further 16 hours at room temperature. Complete conversion was achieved, as judged by .sup.1H NMR, and the amount of overreduced side product (3,3,10,10-tetraethyl-4,9-dioxa-3,10-disiladodecane) was minimal (<12 m/m %).

[0252] Product: triethyl((tetrahydrofuran-2-yl)oxy)silane (86% NMR yield)

.SUP.1.H NMR

[0253] .sup.1H NMR (500 MHz, Chloroform-d) ? 5.57 (t, J=2.6 Hz, 1H), 4.06 (td, J=8.2, 4.7 Hz, 1H), 3.88-3.82 (m, 1H), 2.14-2.04 (m, 1H), 1.94-1.82 (m, 3H), 1.04 (t, J=7.9 Hz, 12H), 0.70 (q, J=8.0 Hz, 7H).

Example 13

Reduction of Methyl 3-phenylpropanoate

[0254] General method for the hydrosilylation of methyl 3-phenylpropanoate ester using catalysts according to the present invention (Scheme 1, Table 1)

[0255] The reaction was performed under inert conditions, neat or using dried solvents. Importantly, the catalyst can operate even in the presence of small amounts of water (technical grade solvents).

[0256] In an oven dried 20 mL vial the ester, methyl 3-phenylpropanoate substrate (0.82 g, 0.79 mL, 1 equiv., 5.0 mmol) was measured in and dissolved in 9 mL abs. toluene. Next, the solution of the catalyst in toluene ((2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2, Entry 16) (23 mg, 1.0 mL, 0.05 M in toluene, 0.01 equiv., 50 ?mol)) was added at room temperature. Then, under stirring, triethylsilane (0.64 g, 0.88 mL, 1.1 equiv., 5.5 mmol) was added dropwise to the reaction mixture. Soon, the reaction started to warm up and the evolution of small amounts of hydrogen gas is observed (from trace amounts of water/alcohols/carboxylic acid). The reaction was further stirred at room temperature for 16 hours, until the end of the conversion of the ester, as judged by NMR or GC-MS. Next, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product triethyl(1-methoxy-3-phenylpropoxy)silane (1.39 g, 4.95 mmol, 99% yield).

[0257] The above process can be applied with the use of the other catalysts compound given in Table 1., with the necessary modifications being within the general knowledge of a skilled person.

.SUP.1.H NMR

[0258] .sup.1H NMR (500 MHz, Benzene-d6) ? 7.18-7.12 (m, 5H), 4.70 (dd, J=5.9, 4.3 Hz, 1H), 3.19 (s, 3H), 2.78-2.73 (m, 2H), 2.06-1.98 (m, 1H), 1.97-1.89 (m, 1H), 1.00 (t, J=7.9 Hz, 9H), 0.61 (q, J=8.0 Hz, 6H).

.SUP.13.C NMR

[0259] .sup.13C NMR (126 MHz, Benzene-d6) ? 142.4 (1C), 128.8 (2C), 128.7 (2C), 126.1 (1C), 98.7 (1C), 53.2 (1C), 39.3 (1C), 31.2 (1C), 7.1 (3C), 5.6 (3C).

Example 14

Reduction of Ethyl 4-bromobutanoate

[0260] ##STR00048##

[0261] In an oven dried 20 mL vial the ester, ethyl 4-bromobutanoate (2.93 g, 2.15 mL, 1 equiv., 15.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (6.70 mg, 300 ?L, 0.05 M in benzene-d6, 0.001 equiv., 15.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (2.27 g, 3.1 mL, 1.3 equiv., 19.5 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (4-bromo-1-ethoxybutoxy)triethylsilane (4.54 g, 14.6 mmol, 97% yield).

.SUP.1.H NMR

[0262] .sup.1H NMR (500 MHz, Chloroform-d) ? 4.81 (t, J=5.0 Hz, 1H), 3.70 (dq, J=9.2, 7.1 Hz, 1H), 3.46-3.36 (m, 3H), 2.03-1.89 (m, 2H), 1.78-1.67 (m, 2H), 1.19 (t, J=7.0 Hz, 3H), 0.98 (t, J=7.9 Hz, 9H), 0.64 (q, J=8.0 Hz, 6H).

Example 15

Reduction of Ethyl 3-bromopropanoate

[0263] ##STR00049##

[0264] In an oven dried 20 mL vial the ester, ethyl 3-bromopropanoate (3.62 g, 2.55 mL, 1 equiv., 20.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (8.94 mg, 400 ?L, 0.05 M In benzene-d6, 0.001 equiv., 20.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (2.56 g, 3.51 mL, 1.1 equiv., 22.0 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (3-bromo-1-ethoxypropoxy)triethylsilane (6.2 g, 21 mmol, 99+% yield).

.SUP.1.H NMR

[0265] .sup.1H NMR (300 MHz, Benzene-d6) ? 4.92 (dd, J=5.7, 4.4 Hz, 1H), 3.56 (dq, J=9.1, 7.1 Hz, 1H), 3.35-3.15 (m, 3H), 2.11-1.90 (m, 2H), 1.06 (t, J=7.0 Hz, 3H), 0.98 (t, J=7.9 Hz, 9H), 0.66-0.54 (m, 6H).

Example 16

Reduction of Ethyl 5-bromopentanoate

[0266] ##STR00050##

[0267] In an oven dried 20 mL vial the ester, ethyl 5-bromopentanoate (4.18 g, 3.17 mL, 1 equiv., 20.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (8.94 mg, 400 ?L, 0.05 M in benzene-d6, 0.001 equiv., 20.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (2.56 g, 3.51 mL, 1.1 equiv., 22.0 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: ((5-bromo-1-ethoxypentyl)oxy)triethylsilane (6.5 g, 20 mmol, 99+% yield).

.SUP.1.H NMR

[0268] .sup.1H NMR (500 MHz, Benzene-d6) ? 4.71 (dd, J=5.8, 4.1 Hz, 1H), 3.62 (dq, J=9.1, 7.1 Hz, 1H), 3.27 (dq, J=9.1, 7.0 Hz, 1H), 2.97 (t, J=6.7 Hz, 2H), 1.61-1.38 (m, 6H), 1.12 (t, J=7.0 Hz, 3H), 1.02 (t, J=8.0 Hz, 9H), 0.64 (q, J=8.0 Hz, 6H).

Example 17

Reduction of Ethyl 6-bromohexanoate

[0269] ##STR00051##

[0270] In an oven dried 20 mL vial the ester, ethyl 6-bromohexanoate (3.35 g, 2.67 mL, 1 equiv., 15.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (6.70 mg, 300 ?L, 0.05 M in benzene-d6, 0.001 equiv., 15.0 ?mol was added at room temperature. Then, under stirring, triethylsilane (1.92 g, 2.64 mL, 1.1 equiv., 16.5 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: ((6-bromo-1-ethoxyhexyl)oxy)triethylsilane (4.9 g, 14 mmol, 96% yield).

.SUP.1.H NMR

[0271] .sup.1H NMR (500 MHz, Benzene-d6) ? 4.76 (dd, J=5.8, 4.4 Hz, 1H), 3.65 (dq, J=9.1, 7.1 Hz, 1H), 3.32 (dq, J=9.1, 7.0 Hz, 1H), 2.95 (t, J=6.8 Hz, 2H), 1.67-1.47 (m, 4H), 1.37-1.28 (m, 2H), 1.21 (q, J=7.6 Hz, 2H), 1.15 (t, J=7.0 Hz, 3H), 1.04 (t, J=7.9 Hz, 9H), 0.66 (q, J=8.0 Hz, 6H).

Example 18

Reduction of Isopropyl 4-Bromobutanoate

[0272] ##STR00052##

[0273] In an oven dried 20 mL vial the ester, isopropyl 4-bromobutanoate (2.09 g, 1 equiv., 10.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (4.47 mg, 200 ?L, 0.05 M in benzene-d6, 0.001 equiv., 10.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (1.28 g, 1.76 mL, 1.1 equiv., 11.0 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (4-bromo-1-isopropoxybutoxy)triethylsilane (2.84 g, 8.73 mmol, 87% yield).

.SUP.1.H NMR

[0274] .sup.1H NMR (500 MHz, Benzene-d6) ? 4.80 (dd, J=5.6, 4.1 Hz, 1H), 3.75 (hept, J=6.2 Hz, 1H), 3.13-3.02 (m, 2H), 1.91-1.75 (m, 2H), 1.70-1.60 (m, 2H), 1.14 (d, J=6.2 Hz, 3H), 1.04-0.95 (m, 12H), 0.62 (q, J=7.7 Hz, 6H).

Example 19

Reduction of Ethyl 2-(2-chloroethoxy)acetate

[0275] ##STR00053##

[0276] In an oven dried 20 mL vial the ester, ethyl 2-(2-chloroethoxy)acetate (1.67 g, 1 equiv., 10.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (4.47 mg, 200 ?L, 0.05 M in benzene-d6, 0.001 equiv., 10.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (1.28 g, 1.76 mL, 1.1 equiv., 11.0 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (2-(2-chloroethoxy)-1-ethoxyethoxy)triethylsilane (2.5 g, 8.8 mmol, 88% yield).

.SUP.1.H NMR

[0277] .sup.1H NMR (300 MHz, Benzene-d6) ? 4.91 (t, J=4.9 Hz, 1H), 3.74-3.61 (m, 1H), 3.44-3.27 (m, 5H), 3.20-3.14 (m, 2H), 1.12 (td, J=7.1, 1.2 Hz, 3H), 1.02 (t, J=7.8 Hz, 9H), 0.65 (q, J=8.3 Hz, 6H).

Example 20

[0278] Reduction of Methyl 2-bromopropanoate

##STR00054##

[0279] In an oven dried 20 mL vial the ester, methyl 2-bromopropanoate (1.67 g, 1.12 mL, 1 equiv., 10.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (4.47 mg, 200.0 ?L, 0.05 M in benzene-d6, 0.001 equiv., 10.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (1.28 g, 1.76 mL, 1.1 equiv., 11.0 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain (2-bromo-1-methoxypropoxy)triethylsilane (2.7 g, 9.5 mmol, 95% yield). The product is a mixture of the possible diastereomers in a 3:1 ratio.

.SUP.1.H NMR

Major Diastereomer:

[0280] .sup.1H NMR (300 MHz, Chloroform-d) ? 4.71 (d, J=4.6 Hz, 1H), 4.08-3.96 (m, 1H), 3.38 (d, J=0.7 Hz, 3H), 1.64 (d, J=6.7 Hz, 3H), 1.05-0.94 (m, 9H), 0.69 (q, J=7.8 Hz, 6H).

Minor Diastereomer:

[0281] .sup.1H NMR (300 MHz, Chloroform-d) ? 4.76 (d, J=3.8 Hz, 1H), 4.00-3.85 (m, 1H), 3.40 (d, J=0.8 Hz, 3H), 1.65 (d, J=6.9 Hz, 3H), 1.00 (t, J=7.9 Hz, 9H), 0.68 (q, J=7.9 Hz, 6H).

Example 21

Reduction of Ethyl 2-(2-bromoethoxy)acetate

[0282] ##STR00055##

[0283] In an oven dried 20 mL vial the ester, ethyl 2-(2-bromoethoxy)acetate (2.11 g, 1 equiv., 10.0 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (44.7 mg, 2.00 mL, 0.05 M in benzene-d6, 0.01 equiv., 100 ?mol) was added at room temperature. Then, under stirring, triethylsilane (1.40 g, 1.92 mL, 1.2 equiv., 12.0 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by .sup.1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (2-(2-bromoethoxy)-1-ethoxyethoxy)triethylsilane (3.2 g, 9.8 mmol, 98% yield).

.SUP.1.H NMR

[0284] .sup.1H NMR (500 MHz, Benzene-d6) ? 4.91 (t, J=4.9 Hz, 1H), 3.67 (dq, J=9.2, 7.1 Hz, 1H), 3.44 -3.32 (m, 5H), 3.01 (t, J=6.1 Hz, 2H), 1.13 (t, J=7.0 Hz, 3H), 1.02 (t, J=7.8 Hz, 9H), 0.65 (qd, J=7.9, 1.4 Hz, 6H).

Example 22

Reduction of Ethyl 4-bromo-2-fluorobutanoate

[0285] ##STR00056##

[0286] In an oven dried 4 mL vial the ester, ethyl 4-bromo-2-fluorobutanoate (533 mg, 1 equiv., 2.50 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (11.2 mg, 500 ?L, 0.05 M in benzene-d6, 0.01 equiv., 25.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (349 mg, 479 ?L, 1.2 equiv., 3.00 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by .sup.1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (4-bromo-1-ethoxy-2-fluorobutoxy)triethylsilane (720 mg, 2.19 mmol, 88% yield).

.SUP.1.H NMR

[0287] .sup.1H NMR (500 MHz, Chloroform-d) ? 4.89 (dd, J=6.9, 3.7 Hz, 1H), 4.62-4.48 (m, 1H), 3.75 (dq, J=9.2, 7.1 Hz, 1H), 3.60-3.48 (m, 3H), 2.31-2.16 (m, 2H), 1.22 (t, J=7.0 Hz, 3H), 1.00 (t, J=7.9 Hz, 9H), 0.68 (q, J=8.1 Hz, 6H).

Example 23

Reduction of Ethyl decanoate

[0288] ##STR00057##

[0289] In an oven dried 500 mL flask the ester, ethyl decanoate (40.0 g, 1 equiv., 200 mmol) was measured in under nitrogen and dissolved in 200 ml dry toluene. Next, the solution of the catalyst in toluene (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (89.2 mg, 3.99 mL, 0.05 M in toluene, 0.001 equiv., 200 ?mol) was added at room temperature. Then, under stirring triethylsilane (25.5 g, 35.1 mL, 1.1 equiv., 220 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: ((1-ethoxydecyl)oxy)triethylsilane (62 g, 0.20 mol, 98% yield)

.SUP.1.H NMR

[0290] .sup.1H NMR (500 MHz, Chloroform-d) ? 4.75 (dd, J=6.2, 4.4 Hz, 1H), 3.69 (dq, J=9.1, 7.1 Hz, 1H), 3.41 (dq, J=9.1, 7.0 Hz, 1H), 1.66 -1.48 (m, 2H), 1.40-1.23 (m, 14H), 1.19 (t, J=7.0 Hz, 3H), 0.98 (t, J=8.0 Hz, 9H), 0.88 (t, J=6.9 Hz, 3H), 0.64 (q, J=7.9 Hz, 6H).

Example 23

Reduction of Ethyl 4-bromopentanoate

[0291] ##STR00058##

[0292] In an oven dried 4 mL vial the ester, ethyl 4-bromopentanoate (1.05 g, 1 equiv., 5.00 mmol) was measured in under nitrogen. Next, the solution of the catalyst in toluene (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (2.23 mg, 100 ?L, 0.05 M in toluene, 0.001 equiv., 5.00 ?mol) was added at room temperature. Then, under stirring, triethylsilane (698 mg, 958 ?L, 1.2 equiv., 6.00 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: ((4-bromo-1-ethoxypentyl)oxy)triethylsilane (1.6 g, 4.9 mmol, 98% yield).

.SUP.1.H NMR

[0293] .sup.1H NMR (500 MHz, Chloroform-d) ? 4.80 (ddd, J=14.8, 5.9, 4.0 Hz, 1H), 4.21-4.11 (m, 1H), 3.70 (dqd, J=9.1, 7.1, 1.9 Hz, 1H), 3.40 (dqd, J=9.2, 7.0, 1.2 Hz, 1H), 1.97 -1.76 (m, 4H), 1.71 (d, J=6.7 Hz, 3H), 1.19 (t, J=7.1 Hz, 3H), 1.03-0.95 (m, 9H), 0.66 (td, J=7.9, 1.7 Hz, 6H).

Example 24

Reduction of Ethyl 4-bromo-2,2-difluorobutanoate

[0294] ##STR00059##

[0295] In an oven dried 4 mL vial the ester, ethyl 4-bromo-2,2-difluorobutanoate (578 mg, 1 equiv., 2.50 mmol) was measured in under nitrogen. Next, the solution of the catalyst in toluene (2-bromo-6-fluorophenyl)bis(2,3,5,6-tetrafluorophenyl)borane (Compound 1) (24.1 mg, 1.00 mL, 0.05 M in toluene, 0.02 equiv., 50.0 ?mol was added at room temperature. Then, under stirring, triethylsilane (349 mg, 479 ?L, 1.2 equiv., 3.00 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain the product: (4-bromo-1-ethoxy-2,2-difluorobutoxy)triethylsilane (448 mg, 1.29 mmol, 52% yield).

.SUP.1.H NMR

[0296] .sup.1H NMR (500 MHz, Chloroform-d) ? 4.73 (dd, J=4.6, 3.8 Hz, 1H), 3.75 (dq, J=9.2, 7.1 Hz, 1H), 3.58-3.47 (m, 3H), 2.62-2.50 (m, 2H), 1.23 (t, J=7.0 Hz, 3H), 0.98 (t, J=8.0 Hz, 9H), 0.70-0.64 (m, 6H).

Example 25

[0297] Reduction of Ethyl 4-bromo-2-methylbutanoate

##STR00060##

[0298] In an oven dried 4 mL vial the ester, ethyl 4-bromo-2-methylbutanoate (1.05 g, 1 equiv., 5.00 mmol) was measured in under nitrogen. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,3,6-trifluorophenyl)borane (Compound 2) (11.2 mg, 500 0.05 M in benzene-d6, 0.005 equiv., 25.0 ?mol) was added at room temperature. Then, under stirring, triethylsilane (698 mg, 958 1.2 equiv., 6.00 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the reaction mixture was passed through a short pad of silica and eluted with hexanes. The filtrate was concentrated in vacuo to obtain (4-bromo-1-ethoxy-2-methylbutoxy)triethylsilane (1.48 g, 4.55 mmol, 91% yield). The product is a mixture of the possible diastereomers in a 3:2 ratio.

[0299] .sup.1H NMR

Major diastereomer:

[0300] 1H NMR (500 MHz, Chloroform-d) ? 4.62 (d, J=3.7 Hz, 1H), 3.72-3.64 (m, 1H), 3.57-3.50 (m, 1H), 3.46-3.38 (m, 2H), 2.06 (dtd, J=14.2, 7.7, 5.1 Hz, 1H), 1.78 -1.67 (m, 2H), 1.19 (t, J=7.0 Hz, 3H), 0.99 (t, J=8.0 Hz, 9H), 0.94 (d, J=6.8 Hz, 3H), 0.65 (q, J=8.0 Hz, 6H).

Minor diastereomer:
.sup.1H NMR (500 MHz, Chloroform-d) ? 4.59 (d, J=4.1 Hz, 1H), 3.72-3.64 (m, 1H), 3.57-3.50 (m, 1H), 3.46-3.38 (m, 2H), 2.16 (dtd, J=14.1, 8.1, 4.6 Hz, 1H), 1.90-1.80 (m, 2H), 1.19 (t, J=7.0 Hz, 3H), 0.99 (t, J=8.0 Hz, 9H), 0.91 (d, J=6.9 Hz, 3H), 0.65 (q, J=8.0 Hz, 6H).

Example 26

Synthesis of (2-bromo-6-fluorophenyl)bis(2,6-difluorophenyl)borane (Compound 9, See Entry 20)

[0301] The compound was prepared as described below and illustrated in schemes 3, 4 and 34.

[0302] Step a) and Step b) are analogues to EXAMPLE 1.

Step c) Synthesis of (2-bromo-6-fluorophenyl)bis(2,6-difluorophenyl)Borane (Compound 9)

##STR00061##

[0303] A 50 mL 3-necked flask was equipped with a reflux condenser and N.sub.2 inlet, Magnesium turnings (0.95 g, 2.2 equiv., 39.2 mmol) were measured in and activated with iodine. Then, 15 mL abs. diethyl ether was added followed by the dropwise addition of 2-chloropropane (3.08 g, 3.57 mL, 2.2 equiv., 39.2 mmol). The solution started to warm up and reflux. Additional 15 mL diethyl ether was added, and dropwise addition of 2-chloropropane was continued to maintain the reflux. In another 250 mL 2-necked flask, 2-bromo-1,3-difluorobenzene (7.56 g, 4.42 mL, 2.2 equiv., 39.2 mmol) was measured in and dissolved in 60 mL abs. diethyl ether, after which it was cooled to 0? C. The previously prepared Grignard solution was added dropwise via syringe in 45 min, keeping the reaction temperature below 5? C. After completion of the addition, the reaction mixture was stirred for 1 h. In a 250 mL Schlenk flask, potassium (2-bromo-6-fluorophenyl)trifluoroborate (Compound 1b) (5.00 g, 1 equiv., 17.8 mmol) was measured in under N.sub.2 suspended in 10 mL abs. diethyl ether and cooled down to ?78? C. The cool (?78? C.) Grignard solution was added via cannula within 20 min, while keeping the temperature under ?60? C. The reaction mixture was left to warm up to 25? C. and was stirred for an additional 18h. Afterwards, the solvent was evaporated at 50? C. in vacuo. Next, 60 mL abs. toluene was added, and the suspension was sonicated for 10 minutes. with the resulting precipitate was filtered off and washed with 2?10 mL abs. toluene. The combined filtrate was then evaporated at 70? C. in vacuo, resulting an off-white solid. Then, 20 mL abs. hexane was added, and the resulting suspension was filtered at ?78? C. to yield the product as a white crystalline powder (2.92 g, 7.10 mmol, 40% yield).

.SUP.1.H NMR

[0304] .sup.1H NMR (500 MHz, Benzene-d6) ? 7.04 (dd, J=7.8, 1.0 Hz, 1H), 6.73 (tt, J=8.3, 6.5 Hz, 2H), 6.66-6.55 (m, 2H), 6.43 (t, J=8.1 Hz, 4H). .sup.19F NMR

[0305] .sup.19 F NMR (282 MHz, Benzene-d6) ? ?97.70 (t, J=7.1 Hz, 4F), ?102.58-?102.69 (m, 1F).

.SUP.13 .C NMR

[0306] Partial .sup.13C NMR (126 MHz, Benzene-d6) ? 166.2 (dd, J=253.3, 11.1 Hz, 4C), 162.9 (d, J=244.5 Hz, 1C), 136.1 (t, J=11.5 Hz, 2C), 131.8 (d, J=9.1 Hz, 1C), 128.1 (d, J=3.2 Hz, 1C), 123.8 (d, J=10.1 Hz, 1C), 113.8 (d, J=23.8 Hz, 1C), 111.6-111.4 (m, 4C).

Example 27

Alternative Reduction of ethyl 4-bromobutanoate using TMDS

[0307] ##STR00062##

[0308] In an oven dried 20 mL vial the ester, ethyl 4-bromobutanoate (1.29 g, 0.95 mL, 1 equiv., 6.60 mmol) was measured in under nitrogen and dissolved in 6.6 ml abs. toluene. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,4,6-trifluorophenyl)borane (Compound 5) (2.95 mg, 132 ?L, 0.05 M in benzene-d6, 0.001 equiv., 6.60 ?mol) was added at room temperature. Then, under stirring, 1,1,3,3-tetramethyldisiloxane (TMDS) (532 mg, 0.70 mL, 0.6 equiv., 3.96 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the solvents were evaporated, and the crude product was purified using flash chromatography on silica gel with hexanes/ethyl acetate gradient elution. After chromatography, the fractions containing the product were concentrated in vacuo to give the product 4,10-bis(3-bromopropyl)-6,6,8,8-tetramethyl-3,5,7,9,11-pentaoxa-6,8-disilatridecane (1.64 g, 3.13 mmol, 95% yield).

.SUP.1.H NMR

.SUP.1.H NMR (500 MHz, Chloroform-d) ? 4.88 (t, J=5.1 Hz, 2H), 3.77-3.68 (m, 2H), 3.47-3.35 (m, 6H), 2.02 -1.91 (m, 4H), 1.79-1.72 (m, 4H), 1.20 (t, J=7.1 Hz, 6H), 0.19-0.16 (m, 12H).

Example 28

[0309] Reduction of Ethyl 3-phenylpropanoate using TMDS

##STR00063##

[0310] In an oven dried 20 mL vial the ester, ethyl 3-phenylpropanoate (1.07 g, 1 equiv., 6.00 mmol) was measured in under nitrogen and dissolved in 6.0 ml abs. toluene. Next, the solution of the catalyst in benzene-d6 (2-bromo-6-fluorophenyl)bis(2,6-difluorophenyl)borane (Compound 9) (2.47 mg, 120 ?L, 0.05 M in benzene-d6, 0.001 equiv., 6.00 ?mol) was added at room temperature. Then, under stirring, 1,1,3,3-tetramethyldisiloxane (TMDS) (467 mg, 0.62 mL, 0.58 equiv., 3.48 mmol) was added dropwise to the reaction mixture. The reaction was stirred overnight. The reaction went to complete conversion, as judged by 1H NMR. Next day, the solvents were evaporated, and the crude product was purified using flash chromatography on silica gel with hexanes/ethyl acetate gradient elution. After chromatography, the fractions containing the product were concentrated in vacuo to give the product 6,6,8,8-tetramethyl-4,10-diphenethyl-3,5,7,9,11-pentaoxa-6,8-disilatridecane (1.15 g, 2.33 mmol, 78% yield).

.SUP.1.H NMR

[0311] .sup.1H NMR (500 MHz, Chloroform-d) ? 7.29-7.24 (m, 4H), 7.20-7.15 (m, 6H), 4.83 (dd, J=6.1, 4.4 Hz, 2H), 3.74 (dq, J=9.3, 7.1 Hz, 2H), 3.39 (dq, J=9.2, 7.0 Hz, 2H), 2.76 2.62 (m, 4H), 2.01 1.84 (m, 4H), 1.21 (td, J=7.0, 1.3 Hz, 6H), 0.13 (d, J=4.1 Hz, 12H).

[0312] General Remarks

[0313] During the evaluation/explanation of the results, the following theoretical assumptions can be made. At first, the steric factor should be taken into consideration, because the ortho-substituents on the aryl rings significantly inhibit the access to the boron center. Thus, the principle of size exclusion is realized, the essence of which is that the boranes do not form stable adducts with the Lewis basic components present in the reaction mixture, but the triethylsilane still has access to them. This improves the selectivity, although significant steric congestion may lead to a decrease in the reactivity. Another important factor is the Lewis acidity of boranes. Increasing this also increases the reactivity to a certain level, but beyond this level, the electron-withdrawing substituents excessively stabilize the forming hydride intermediate, thereby reducing its reactivity. However, increasing the reactivity of boranes can also reduce the selectivity. A further aspect is the reactivity of the substrate (ester or lactone) to be reduced. In case of a reactive substrate a less reactive catalyst of the present invention can be proper and vice versa. The selection of the proper catalyst to a specific substrate needs a fine-tuning of the substituent pattern of the catalyst (increasing or decreasing the Lewis acid character of it by the use of the substituents providing the desired electron withdrawing effect). The theoretical selection can be made on the basis of the expectable knowledge of a skilled person and the success of the selected substituent pattern can be checked by relatively simple experiments, i.e. without undue burden on the skilled person working on this filed. This is a very important feature of the present invention which allows a general use of the invented catalyst family.