Perfluoroalkyl group-containing bismuth compounds as lewis acid catalysts

Abstract

The invention relates to perfluoroalkyl group-containing bismuth compounds as Lewis acid catalysts, to specific compounds, and to the method for the production thereof.

Claims

1. A compound, which is of formula (I)
(C.sub.mF.sub.2m+1).sub.nBiX.sub.3-n(I), wherein m in each case, independently of one another, denotes 2, 3 or 4; n denotes 1 or 2 and X denotes F, Cl, Br or OSO.sub.2CF.sub.3, or which is of formula (IIIa) or (IIIb)
ArBi(C.sub.mF.sub.2m+1).sub.2(IIIa),
Ar.sub.2Bi(C.sub.mF.sub.2m+1)(IIIb), wherein m in each case, independently of one another, denotes 2, 3 or 4 and Ar in each case, independently of one another, denotes an aryl group having 6 to 10 C atoms, which may be substituted.

2. A compound according to claim 1, which is of formula (I)
(C.sub.mF.sub.2m+1).sub.nBiX.sub.3-n(I), wherein m in each case, independently of one another, denotes 2, 3 or 4; n denotes 1 or 2 and X denotes F, Cl, Br or OSO.sub.2CF.sub.3.

3. A compound according to claim 2, wherein m denotes 2 or 4.

4. A compound according to claim 2, wherein the compound of formula (I) is Bi(C.sub.2F.sub.5).sub.2Cl.

5. A compound according to claim 2, wherein the perfluoroalkyl group (C.sub.mF.sub.2m+1) in formula (I) is the same on each occurrence.

6. A compound according to claim 2, wherein X denotes Cl.

7. A process for preparing the compound of formula (I),
(C.sub.mF.sub.2m+1).sub.nBiX.sub.3-n(I), wherein m in each case, independently of one another, denotes 2, 3 or 4; n denotes 3 and X denotes F, Cl, Br or OSO.sub.2CF.sub.3, comprising reacting a compound of formula (II)
(C.sub.mF.sub.2m+1)Li(II), wherein m denotes 2, 3 or 4, with bismuth trichloride, bismuth tribromide or bismuth tristriflate, where the conditions of the reaction are that both the water content and the oxygen content are a maximum of 100 ppm.

8. A process for preparing the compound of claim 2, comprising reacting a compound of formula (II)
(C.sub.mF.sub.2m+1)Li(II), wherein m in each case, independently of one another, denotes 2, 3 or 4, with dichloroarylbismuthane or chloro(diaryl)bismuthane, wherein aryl in the bismuthane denotes an aryl group having 6 to 10 C atoms, which may be substituted or unsubstituted, and the resultant intermediates of the formula (Ma) or (Mb)
ArBi(C.sub.mF.sub.2m+1).sub.2(IIIa) or
Ar.sub.2Bi(C.sub.mF.sub.2m+1)(IIIb), are subsequently reacted with hydrogen chloride, hydrogen bromide, anhydrous HF or CF.sub.3SO.sub.3H to give a compound of formula (I), wherein Ar in each case, independently of one another, denotes an aryl group having 6 to 10 C atoms, which may be substituted or unsubstituted, and where the conditions of the reaction with the compound of the formula (II) are that both the water content and the oxygen content are a maximum of 100 ppm.

9. A compound according to claim 1, which is of formula (IIIa) or (IIIb)
ArBi(C.sub.mF.sub.2m+1).sub.2(IIa),
Ar.sub.2Bi(C.sub.mF.sub.2m+1)(IIIb), wherein m in each case, independently of one another, denotes 2, 3 or 4 and Ar in each case, independently of one another, denotes an aryl group having 6 to 10 C atoms, which may be substituted.

10. A method for Lewis acid catalysis of a reaction, comprising performing said reaction in the presence of at least one compound according to claim 9 as the Lewis acid catalyst.

11. A compound according to claim 2, wherein n denotes 1.

12. A compound according to claim 2 The method, wherein n denotes 2.

13. A compound according to claim 2, wherein the compound of formula (I) is Bi(C.sub.2F.sub.5)Cl.sub.2.

14. The compound according to claim 9, wherein the aryl group having 6 to 10 C atoms denotes phenyl or naphthyl, which may be mono- or polysubstituted by alkyl, fluorinated alkyl, Oalkyl or N(alkyl).sub.2.

15. The compound according to claim 9, wherein the aryl group having 6 to 10 C atoms denotes unsubstituted phenyl or naphthyl.

16. The process according to claim 8, wherein any of the aryl groups having 6 to 10 C atoms denotes phenyl or naphthyl, which may be mono- or polysubstituted by alkyl, fluorinated alkyl, Oalkyl or N(alkyl).sub.2.

17. The process according to claim 8, wherein any of the aryl groups having 6 to 10 C atoms denotes unsubstituted phenyl or naphthyl.

Description

EXAMPLES

Example 1

Synthesis of tris(pentafluoroethyl)bismuthane, Bi(C2F5)3

(1) A)

(2) ##STR00001##

(3) 50 ml (100 mmol) of a 2 M solution of n-buthyllithium in pentane in 200 ml of dry diethyl ether are initially introduced into a 500 ml Schlenk flask and degassed at 90 C. in a counterstream of nitrogen. 12.3 g (102.5 mmol) of pentafluoroethane are condensed in at 80 C., and the mixture is stirred at the same temperature for 30 minutes. 6.31 g (20.0 mmol) of bismuth trichloride, BiCl.sub.3, are added in a counterstream of nitrogen. The reaction mixture is stirred at 80 C. for 60 minutes and then warmed to 0 C. over the course of 4 hours. The reaction mixture is filtered under an inert-gas atmosphere, and the residue is washed twice with 20 ml of dry n-pentane each time. The reaction mixture is evaporated in a static vacuum (70 mbar). The remaining solvent is removed in a sublimation apparatus in a high vacuum, and the reaction product is sublimed on a cold finger cooled with dry ice (50 C. to 30 C.). After warming to room temperature, 7.16 g of tris(pentafluoroethyl)bismuthane, Bi(C.sub.2F.sub.5).sub.3, are obtained as a colourless liquid. Yield (based on bismuth trichloride): 63% (12.6 mmol).

(4) Melting point: 10 C.

(5) The NMR data correspond to the values known from the literature [D. Naumann, W. Tyrra, J. Organomet. Chem. 1987, vol. 334, pp. 323-328].

(6) TABLE-US-00001 TABLE NMR data of tris(pentafluoroethyl)bismuthane, Bi(C.sub.2F.sub.5).sub.3, in CH.sub.3CN Nucleus [ppm] Splitting J [Hz] Assignment .sup.19F 82.1 s CF.sub.3CF.sub.2 100.1 s CF.sub.3CF.sub.2 .sup.13C,.sup.19F-DEPT 45nd 122.6 qt .sup.1J.sub.CF = 285 CF.sub.3CF.sub.2 160.9 m CF.sub.3CF.sub.2

(7) TABLE-US-00002 TABLE Mass spectrometry data of tris(pentafluoroethyl)bismuthane, Bi(C.sub.2F.sub.5).sub.3, EI-TOF (gas inlet), positive, 70 eV. m/z Rel. intensity (%) Fragment 466.9 50 [BiF(C.sub.2F.sub.5).sub.2].sup.+ 346.9 100 [BiF[(C.sub.2F.sub.5)].sup.+

(8) B)

(9) ##STR00002##

(10) A 1.6 M solution of n-butyllithium in hexane (0.80 ml, 1.28 mmol) is added to a solution of 171 mg (0.44 mmol) of P(C.sub.2F.sub.5).sub.3 in Et.sub.2O (10 ml) at 65 C., and the mixture is stirred for 10 minutes. 0.15 g (0.48 mmol) of BiCl.sub.3 are added at the same temperature, and the reaction mixture is slowly warmed to room temperature. The solution is investigated by NMR spectroscopy. The NMR data confirm the formation of Bi(C.sub.2F.sub.5).sub.3.

Example 2

Preparation of bis(pentafluoroethyl)phenylbismuthane, PhBi(C2F5)2

(11) ##STR00003##

(12) 22 ml (44.0 mmol) of a 2 M solution of n-buthyllithium in pentane in 100 ml of Et.sub.2O are initially introduced in a 250 ml Schlenk flask and degassed at 80 C. 5.40 g (45 mmol) of pentafluoroethane are condensed in at 80 C., and the mixture is stirred at the same temperature for 25 minutes. 3.87 g (10.8 mmol) of dichlorophenylbismuthane are added, and the mixture is stirred in a cold bath at 80 C. for 3.5 hours. The suspension is filtered in an inert-gas atmosphere and evaporated in a static high vacuum. The remaining solvent is removed in a sublimation apparatus in a high vacuum and at an oil-bath temperature of 80 C., and the reaction product is sublimed on a cold finger cooled with dry ice (35 C.). Warming to room temperature gives 4.22 g of bis(pentafluoroethyl)phenylbismuthane, PhBi(C.sub.2F.sub.5).sub.2, as a colourless liquid.

(13) Yield (based on dichlorophenylbismuthane): 8.1 mmol, 75%.

(14) Melting point: 15 C.

(15) The product is characterised by means of NMR and IR spectroscopy and by mass spectrometry.

(16) TABLE-US-00003 TABLE NMR data of bis(pentafluoroethyl)phenylbismuthane, PhBi(C.sub.2F.sub.5).sub.2, in CD.sub.3CN. Nucleus [ppm] Splitting J [Hz] Assignment .sup.1H 8.2 d .sup.3J.sub.HH = 7 ortho H 7.7 t .sup.3J.sub.HH = 7 meta H 7.5 t .sup.3J.sub.HH = 7 para H .sup.19F 82.4 m (CF.sub.3CF.sub.2).sub.2Bi Ph 105.8 s (CF.sub.3CF.sub.2).sub.2Bi Ph .sup.13C-CPD; 170.4 s quart. C .sup.1H,.sup.13C- 138.7 s ortho C HMBC 132.0 s meta C 130.1 s para C .sup.13C,.sup.19F- 122.3 qm .sup.1J.sub.CF = 283 CF.sub.3CF.sub.2 DEPT45; .sup.13C,.sup.19F- 148.3 tm CF.sub.3CF.sub.2 HMBC

(17) TABLE-US-00004 TABLE Mass spectrometry data of bis(pentafluoroethyl)phenyl- bismuthane, PhBi(C.sub.2F.sub.5).sub.2, EI-TOF (gas inlet), positive, 70 eV. rel. intensity m/z (%) Fragment 405.0 56 [(C2F5)BiPH]+ 286.1 62 [PhBi]+ 209.0 91 Bi+ .Math. IR: {tilde over (v)} = 3065 (w), 2965 (w), 1303 (m), 1182 (s), 1070 (s), 896 (s), 726 (s), 691 (m), 600 (w) 533 (w), 442 (w)

Example 3

Preparation of bis(pentafluoroethyl)chlorobismuthane, (C2F5)2BiCl

(18) ##STR00004##

(19) 4.02 g (7.7 mmol) of bis(pentafluoroethyl)phenylbismuthane, PhBi(C.sub.2F.sub.5).sub.2, are initially introduced in a 800 ml Young's tap ampoule and degassed. 1.09 g (30.0 mmol) of hydrogen chloride are condensed in, and the mixture is stirred at an oil-bath temperature of 60 C. for 2.5 h. Excess hydrogen chloride is removed by condensation, and the residue is sublimed at 90 C. in a high vacuum, giving bis(pentafluoroethyl)chlorobismuthane, (C.sub.2F.sub.5).sub.2BiCl, as a yellow solid. Yield (based on bis(pentafluorethyl)phenylbismuthane): 3.45 g (7.2 mmol, 92%). Melting point: 75-76 C. The product is characterised by means of NMR and IR spectroscopy and by mass spectrometry.

(20) TABLE-US-00005 TABLE NMR data of bis(pentafluoroethyl)chlorobismuthane, (C.sub.2F.sub.5).sub.2BiCl, in CH.sub.3CN. Nucleus [ppm] Splitting J [Hz] Assignment 19F 80.6 s CF.sub.3CF.sub.2 103.0 s CF.sub.3CF.sub.2

(21) TABLE-US-00006 TABLE NMR data of bis(pentafluoroethyl)chlorobismuthane, (C.sub.2F.sub.5).sub.2BiCl, in CH.sub.2Cl.sub.2. Nucleus [ppm] Splitting J [Hz] Assignment 19F 80.8 s CF.sub.3CF.sub.2 101.7 AABB CF.sub.3CF.sub.2

(22) TABLE-US-00007 TABLE Mass spectrometry data of bis(pentafluoroethyl)- chlorobismuthane, (C.sub.2F.sub.5).sub.2BiCl, EI-TOF (gas inlet), positive, 70 eV. m/z rel. intensity (%) Fragment 467.1 20 [BiF(C.sub.2F.sub.5).sub.2].sup.+ 447.1 33 [Bi(C.sub.2F.sub.5).sub.2].sup.+ 347.1 48 [BiF[(C.sub.2F.sub.5)].sup.+ 328.1 6 [Bi(C.sub.2F.sub.5)].sup.+ 247.1 10 [BiF.sub.2].sup.+ 209.0 59 Bi.sup.+ .Math. IR: {tilde over (v)} = 1301 (m), 1190 (s), 1129 (m), 1082 (s), 895 (s), 730 (m), 600 (m), 534 (w).

Example 4

Preparation of pentafluoroethyldiphenylbismuthane, Ph2BiC2F5

(23) A)

(24) ##STR00005##

(25) 20 ml (40 mmol, 2 M in n-pentane) of n-BuLi in 150 ml of diethyl ether are initially introduced into a 500 ml Schlenk flask and degassed at 80 C. 5.4 g (45 mmol) of pentafluoroethane are condensed in, and the mixture is stirred at the same temperature for 10 min. 7.97 g (20 mmol) of chloro(diphenyl)bismuthane are added, the mixture is stirred at 60 C. for 4 h and subsequently warmed to room temperature. All volatile constituents are removed in a high vacuum, the residue obtained is taken up in n-pentane, filtered in an inert-gas atmosphere and washed with n-pentane. Removal of the solvent gives pentafluoroethyl(diphenyl)bismuthane, Ph.sub.2BiC.sub.2F.sub.5, in the form of colourless crystals, which change colour to yellow-brown after a short time. Yield (based on chloro(diphenyl)bismuthane): 6.20 g (12.9 mmol, 65%).

(26) IR: {tilde over ()}; =3052 (w), 2957 (w), 1303 (m), 1568 (w), 1475 (w), 1428 (w), 1308 (m), 1262 (w), 1176 (s), 1075 (s), 903 (m), 800 (w), 724 (s), 692 (s), 596 (m) 533 (w), 442 (m)

(27) TABLE-US-00008 TABLE NMR data of pentafluoroethyldiphenylbismuthane in CD.sub.2Cl.sub.2. Nucleus [ppm] Splitting J [Hz] Assignment .sup.1H 7.9 d .sup.3J.sub.HH = ortho H 7.2 7.6 t .sup.3J.sub.HH = meta H 7.4 7.4 t .sup.3J.sub.HH = para H 7.4 .sup.19F 81.6 s CF.sub.3CF.sub.2 105.6 AABB CF.sub.3CF.sub.2 .sup.13C-CPD 160.5 s quart. C .sup.1H,.sup.13C-HMBC 137.8 s ortho C 131.1 s meta C 128.9 s para C .sup.13C,.sup.19F- 201.5 s CF.sub.3CF.sub.2 DEPT45; .sup.13C,.sup.19F-HMBC 129.4 s CF.sub.3CF.sub.2

(28) B)

(29) ##STR00006##

(30) 80 ml of diethyl ether are initially introduced into a 250 ml Schlenk flask and degassed at 196 C. 2.95 g (7.6 mmol) of tris(pentafluoroethyl)phosphine, (C.sub.2F.sub.5).sub.3P, are condensed in and brought to 65 C. 9.43 g (22.2 mmol; 13.9 ml) of a 1.6 M solution of n-BuLi in hexane are added to this mixture, which is then stirred at the same temperature for 15 min. 8.75 g (22.0 mmol) of chloro(diphenyl)bismuthane are added to the reaction mixture, which is then warmed to 0 C. for 3 h with stirring. The suspension obtained is filtered under an inert-gas atmosphere, the residue is washed with a little diethyl ether, and all volatile constituents of the filtrate are removed in a high vacuum. The residue obtained is taken up in 100 ml of n-pentane. The solution is evaporated until the first crystals form, and the product is crystallised out by cooling to 28 C. The crystals are washed with a little n-pentane and dried in a high vacuum, giving pentafluoroethyl-(diphenyl)bismuthane, Ph.sub.2BiC.sub.2F.sub.5, in the form of colourless, hydrolysis-sensitive crystals. Yield (based on chloro(diphenyl)bismuthane): 8.57 g (17.8 mmol, 81%).

(31) The product is characterised by means of NMR and IR spectroscopy. The NMR and IR data correspond to the values given in Example 4A).

Example 5

Preparation of pentafluoroethyldichlorobismuthane, (C2F5)BiCl2

(32) ##STR00007##

(33) 6.20 g (12.9 mmol) of diphenyl(pentafluoroethyl)bismuthane, Ph.sub.2BiC.sub.2F.sub.5, are taken up in 25 ml of diethyl ether and transferred into an 800 ml Young's tap ampoule. The solvent is removed in a high vacuum, and 1.46 g (40 mmol) of hydrogen chloride are condensed in. The reaction mixture is stirred at an oil-bath temperature of 60 C. for 20 h. All volatile constituents are removed by condensation, the residue is taken up in dichloromethane and transferred into a 100 ml Schlenk flask. Sublimation in a high vacuum at an oil-bath temperature of 90 C. and a cold-finger temperature of 78 C. gives pentafluoroethyldichlorobismuthane, C.sub.2F.sub.5BiCl.sub.2, as a yellow solid.

(34) Yield (based on pentafluoroethyl(diphenyl)bismuthane): 4.67 g (11.7 mmol, 91%).

(35) Melting point: 104 C.

(36) The product is characterised by means of NMR, and IR spectrometry.

(37) TABLE-US-00009 TABLE NMR data of pentafluoroethyldichlorobismuthane, C.sub.2F.sub.5BiCl.sub.2, in CH.sub.3CN. Nucleus [ppm] Splitting J [Hz] Assignment .sup.19F 79.5 s .sup.1J.sub.CF = 283 CF.sub.3CF.sub.2 .sup.2J.sub.CF = 44 105.2 s .sup.1J.sub.CF = 333 CF.sub.3CF.sub.2 .sup.19F,.sup.13C-HMBC 129.42 .sup.1J.sub.CF = 283 CF.sub.3CF.sub.2 .sup.2J.sub.CF = 44 201.45 .sup.1J.sub.CF = 333 CF.sub.3CF.sub.2 .sup.2J.sub.CF = 27 IR: {tilde over (v)} = 1301 (m), 1267 (w), 1103 (s), 1073 (s), 897 (s), 729 (s), 603 (m), 584 (w), 531 (w).

Example 6

Preparation of bis(pentafluoroethyl)fluorobismuthane

(38) ##STR00008##

(39) 366 mg (2.885 mmol) of silver fluoride are added to a solution of (C.sub.2F.sub.5).sub.2BiCl (1.38 g, 2.86 mmol) in a mixture of dichloromethane (10 ml) and acetonitrile (10 ml) in a counterstream of nitrogen. The reaction mixture is stirred at room temperature with exclusion of light for 2.5 h. The solid which precipitates out is filtered off under an inert-gas atmosphere, and the filtrate is evaporated in a high vacuum. Drying in a high vacuum gives (C.sub.2F.sub.5).sub.2BiF as a colourless, slightly crystalline solid. Yield is 1.13 g (2.42 mmol, 85%, based on (C.sub.2F.sub.5).sub.2BiCl).

(40) Decomposition point: >200 C.

(41) TABLE-US-00010 TABLE NMR data of (C.sub.2F.sub.5).sub.2BiF, in CD.sub.3CN Nucleus [ppm] Splitting J [Hz] Assignment .sup.19F 81.8 s .sup.1JCF = CF3CF2 282 108.4 s CF3CF2 171.9 s BiF .sup.13C,.sup.19F- 125.7 s .sup.1JCF = CF3CF2 DEPT45; 282 .sup.13C,.sup.19F- 175.9 CF3CF2 HMBC IR (solid): {tilde over (v)} = 429 (vw), 535 (vw), 588 (vw), 602 (w), 732 (m), 899 (s), 1079 (s), 1186 (s), 1303 (m), 1648 (vw) cm.sup.1.

Example 7

Bismuth(III)-Catalysed Diels-Alder Reaction

(42) ##STR00009##

(43) The Diels-Alder reaction of maleic anhydride and 1,3-cyclohexadiene to give 3,4,7,7-tetrahydro-4,7-ethaneisobenzofuran-1,3-dione is carried out at RT in dichloromethane as solvent. The solution rapidly becomes lemon-yellow, with the colouration becoming weaker in the course of the reaction. The following tables show the reaction conditions, weights and volumes of the starting materials and catalysts.

(44) TABLE-US-00011 TABLE Reaction conditions, starting material weights, volumes and conversions of the Diels-Alder reaction. Cat Maleic 1,3- amount, anhydride, Cyclohexadiene, Time, Conversion Cat mol % g (mmol), 1 eq. ml (mmol), 1.5 eq. min %* BiCl.sub.3 5 0.84 (8.6) 1.2 (12.6) 20 97 (C.sub.2F.sub.5)BiCl.sub.2 1 0.74 (7.5) 1.1 (11.5) 30 97 (C.sub.2F.sub.5).sub.2BiCl 1 0.42 (4.3) 0.6 (6.3) 30 89 *Conversion calculations based on .sup.1H- and .sup.13C-NMR spectroscopy measurements based on maleic anhydride.

(45) The results confirm that (C.sub.2F.sub.5)BiCl.sub.2 and (C.sub.2F.sub.5).sub.2BiCl are significantly more active catalysts in the Diels-Alder reaction compared with BiCl.sub.3.

Example 8

Cyanosilylation Catalysed by tris(pentafluoroethyl)bismuthane, Bi(C2F5)3

(46) ##STR00010##

(47) The cyanosilylation of benzaldehyde using trimethylsilyl cyanide to give 2-phenyl-2-(trimethylsilloxy)acetonitrile is carried out at room temperature in CH.sub.2Cl.sub.2 or 1-ethyl-3-methylimidazolium tris(pentafluorethyl)trifluorophosphate (EMIM FAP) as solvent. The table below shows the reaction conditions, weights and volumes of the starting materials and catalysts.

(48) TABLE-US-00012 TABLE Reaction conditions, starting material weights, volumes and conversions of the cyanosilylation. Cat amount, Trimethylsilyl mol %, Benzaldehyde, cyanide, Conversion, Cat (solvent) ml (mmol) ml (mmol) Time, h %* (C.sub.2F.sub.5).sub.3Bi 5 (CH.sub.2Cl.sub.2) 0.2 (2.0) 0.4 (3.2) 63 44 5 (EMIM 0.2 (0.2) 0.3 (2.4) 19 66 FAP) *Conversion calculations based on .sup.1H- and .sup.13C-NMR spectroscopy measurements based on benzaldehyde.

(49) The results show that, due to the good solubility of (C.sub.2F.sub.5).sub.3Bi in the hydrophobic ionic liquid, the catalytic activity of (C.sub.2F.sub.5).sub.3Bi in EMIM FAP is significantly increased compared with conventional organic solvents, such as CH.sub.2Cl.sub.2.