GROUP 5 METAL COMPLEXES FOR PRODUCING AMINE-FUNTIONALIZED POLYOLEFINS
20220363786 · 2022-11-17
Inventors
Cpc classification
B01J2540/40
PERFORMING OPERATIONS; TRANSPORTING
C08F2810/40
CHEMISTRY; METALLURGY
B01J31/1616
PERFORMING OPERATIONS; TRANSPORTING
C07C275/28
CHEMISTRY; METALLURGY
C08F210/16
CHEMISTRY; METALLURGY
C08F210/16
CHEMISTRY; METALLURGY
B01J31/2404
PERFORMING OPERATIONS; TRANSPORTING
B01J2231/4211
PERFORMING OPERATIONS; TRANSPORTING
C07C209/60
CHEMISTRY; METALLURGY
B01J31/2243
PERFORMING OPERATIONS; TRANSPORTING
C08L23/36
CHEMISTRY; METALLURGY
International classification
Abstract
This application pertains to group 5 metal complexes having the structure of Formula I: and their potential utility in catalyzing amination of polyolefins having alkene groups.amine-
##STR00001##
Claims
1-84. (canceled)
85. A method for amination of a polyolefin having at least one alkene group, the method comprising: (i) reacting a secondary amine-containing moiety with the polyolefin in the presence of a metal complex, the metal complex having the structure of Formula I: ##STR00210## wherein: (i) R.sup.1 and R.sup.2 are each independently; a C.sub.1-C.sub.40 substituted or unsubstituted linear, branched or cyclic alkyl, alkenyl or alkynyl; a substituted or unsubstituted aryl; or a substituted or unsubstituted heterocyclic group; or R.sup.1 and R.sup.2 are bonded together thereby forming, together with the nitrogen atom they are both bound to, a heterocycle; and R.sup.3 is H; a C.sub.1-C.sub.40 substituted or unsubstituted linear, branched or cyclic alkyl, alkenyl or alkynyl; a substituted or unsubstituted aryl; or a substituted or unsubstituted heterocyclic group; or (ii) R.sup.1 is H; a C.sub.1-C.sub.40 substituted or unsubstituted linear, branched or cyclic alkyl, alkenyl or alkynyl; a substituted or unsubstituted aryl; or a substituted or unsubstituted heterocyclic group; and R.sup.3 is bonded together with R.sup.2 to form a heterocycle; M is a group 5 metal; a=0 to 4 and b=0 to 4, wherein the sum of a and b is 4; each X is a halogen substituent; and each R.sup.4 is independently H; or a C.sub.1-C.sub.20 substituted or unsubstituted, linear, branched or cyclic alkyl, optionally comprising heteroatoms.
86. The method of claim 85, wherein each X is independently Cl or Br, a=1 or 2 and b=2 or 3.
87. The method of claim 86, wherein a=1 or.
88-91. (canceled)
92. The method of claim 85, wherein R.sup.3 is bonded together with R.sup.2 to form, together with each of the nitrogen atoms they are bound to, a 5-membered ring, which optionally may be substituted.
93. The method of claim 92, having the structure: ##STR00211## wherein R.sup.1 is methyl, tert-butyl, phenyl, cyclohexyl or adamantyl.
94. The method of claim 85, wherein R.sup.4 is —CH.sub.2Si(CH.sub.3).sub.3.
95. The method of claim 85, wherein M is tantalum (Ta).
96-101. (canceled)
102. The method of claim 85, wherein the metal complex is: ##STR00212##
103-104. (canceled)
105. The method of claim 85, wherein the at least one alkene group comprises at least one vinyl group.
106. The method of claim 85, wherein the at least one alkene group comprises at least one pendant alkene group.
107-108. (canceled)
109. The method of claim 85, wherein the polyolefin is a vinyl-terminated polyolefin.
110. The method of claim 85, wherein the polyolefin comprises a polypropylene.
111. (canceled)
112. The method of claim 85, wherein the polyolefin comprises a poly(ethylene-co-propylene) copolymer.
113. (canceled)
114. The method of claim 85, wherein the molecular weight of the polyolefin is in the range of about 100 g/mol to about 10,000 g/mol.
115-117. (canceled)
118. The method of claim 85, wherein the reaction conditions comprise a reaction temperature in the range from 110° C. to 165° C.
119. (canceled)
120. The method of claim 85, wherein the reaction conditions comprise a solvent.
121-122. (canceled)
123. The method of claim 120, wherein the solvent comprises toluene.
124-127. (canceled)
128. The method of claim 85, wherein the metal complex is generated in situ from a group 5 metal salt of Formula VII
MX.sub.c(R.sup.4).sub.d (Formula VII) wherein: M is a group 5 metal; c=1 to 5 and d=0 to 4, wherein the sum of c and d is 5; and each R.sup.4 is independently H; or a C.sub.1-C.sub.20 substituted or unsubstituted, linear, branched or cyclic alkyl, optionally comprising heteroatoms, in combination with an amide of Formula VIII ##STR00213## (i) R.sup.1 and R.sup.2 are each independently H; a C.sub.1-C.sub.40 substituted or unsubstituted linear, branched or cyclic alkyl, alkenyl or alkynyl; a substituted or unsubstituted aryl; or a substituted or unsubstituted heterocyclic group; or R.sup.1 and R.sup.2 are bonded together thereby forming, together with the nitrogen atom they are both bound to, a heterocycle; and R.sup.3 is H; a C.sub.1-C.sub.40 substituted or unsubstituted linear, branched or cyclic alkyl, alkenyl or alkynyl; a substituted or unsubstituted aryl; or a substituted or unsubstituted heterocyclic group; or (ii) R.sup.1 is H; a C.sub.1-C.sub.40 substituted or unsubstituted linear, branched or cyclic alkyl, alkenyl or alkynyl; a substituted or unsubstituted aryl; or a substituted or unsubstituted heterocyclic group; and R.sup.3 is bonded together with R.sup.2 to form a heterocycle.
129-144. (canceled)
145. The method of claim 85, wherein the secondary amine-containing moiety is: ##STR00214## wherein Z is H, OCF.sub.3, F, Cl, Br, I, or OCH.sub.3.
146. The method of claim 85, wherein the secondary amine-containing moiety is N-methylaniline, N-methylcyclohexylamine, or N-methylbutylamine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0149] In drawings which illustrate embodiments of the invention,
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DETAILED DESCRIPTION
Definitions
[0208] “Catalyst”, as used herein, refers to a chemical compound that accelerates a chemical reaction without itself being affected. “Catalyst” may be used interchangeably with terms such as “pre-catalyst”, “catalyst system”, or “catalytic system”. “Catalyst”, as used herein, includes catalytic intermediates or species formed in situ.
[0209] “Group 5 metal” as used herein, refers to the d-electron comprising transition metals listed in the periodic table of the elements as group 5, including transition metals vanadium (V), niobium (Nb), tantalum (Ta), and dubnium (Db).
[0210] “Atactic polypropylene”, as used herein, refers to a polymer wherein the methyl group of the propylene units has no regular alignment.
[0211] “Copolymer”, as used herein, refers to a polymer derived from more than one species of monomer.
[0212] “Hydroaminoalkylation”, as used herein, refers to a reaction between a secondary amine containing moiety and an olefin. A catalyst may often be used to promote such reaction.
[0213] “Secondary amine”, as used herein, refers to an amine in which the amino group is directly bonded to two C-atoms of any hybridization. The two C-atoms in α-position to the N-atom may be sp.sup.3 hybridized.
[0214] “Olefin” or “alkene”, as used herein, refers to an unsaturated hydrocarbon containing one or more pairs of C-atoms linked by a double bond.
[0215] “TOF”, as used herein, refers to “turnover frequency”.
[0216] “Vinyl”, as used herein, refers to a functional group with the formula —CH═CH.sub.2.
[0217] A “pendant” group, as used herein, refers to a side group (or offshoot) from the main chain (or backbone) of a polyolefin.
[0218] Throughout this specification, unless the context requires otherwise, the words “comprise”, “comprising” and the like, are to be construed in an inclusive sense as opposed to an exclusive sense, that is to say, in the sense of “including, but not limited to”.
[0219] This disclosure relates to the discovery that rapid C—H alkylation of unprotected secondary arylamines with unactivated alkenes, particularly pendant and terminal alkene groups of polyolefins, can be achieved with metal complex catalysts comprising a combination of a tantalum (Ta) organometallic reagent (e.g. Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2) and a ureate N,O chelating-ligand salt.
Materials and Methods
[0220] The procedures described herein are given for the purposes of example and illustration only and should not be considered to limit the spirit or scope of the invention.
1. Materials
[0221] All reactions were performed under a N.sub.2 atmosphere using Schlenk or glovebox techniques, unless otherwise stated. TaCl.sub.5 (Strem), Ta(NMe.sub.2).sub.5 (Strem), and (chloromethyl)trimethylsilane (Sigma) were used as received. NaN(SiMe.sub.3).sub.2 (Sigma) was recrystallized from a hot toluene solution before use. All amines and alkenes were commercially available, dried over CaH.sub.2 and distilled and degassed prior to use in catalytic experiments. [Ta(NMe.sub.2).sub.3Cl.sub.2].sub.2, TaMe.sub.3Cl.sub.2, Ta(CH.sub.2CMe.sub.3).sub.3Cl.sub.2, and Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 were synthesized according to literature protocols (Chem. Int. Ed. 48, 4892-4894; Synthesis 46, 2884-2896; Chem. Res 48: 2576-2586; Inorg. Chem. 20: 1859-1866; J. Am. Chem. Soc. 100: 2389-2399; Dalton Trans. 40, 7777-7782). All glassware was dried in a 180° C. oven overnight before use. Toluene, hexanes and Et.sub.2O were dried over an activated alumina column and stored over activated molecular sieves (4 Å). d.sub.6-Benzene and d.sub.8-toluene were dried over sodium/ketyl and distilled prior to use. Experiments conducted on NMR tube scale were performed in J. Young NMR tubes (8″×5 mm) sealed with screw-type Teflon caps.
2. Instrumentation
[0222] .sup.1H and .sup.13C NMR spectra were recorded on Bruker 300 MHz, or 400 MHz, Avance spectrometers at ambient temperature. Chemical shifts (δ) are given relative to the corresponding residual protio solvent and are reported in parts per million (ppm). Coupling constants J are given in Hertz (Hz). The following abbreviations are used to indicate signal multiplicity: s=singlet, d=doublet, t=triplet, q=quartet, m=multiplet, and br=broad. Assignment of the signals was carried out using 1D (.sup.1H, .sup.13C{.sup.1H}) and 2D (COSY, HSQC and HMBC) NMR experiments.
3. Synthesis
3.1 Proligands
[0223] The synthesis of proligands is generally discussed below, with reference to particular exemplified proligands.
General Procedure for the Synthesis of Urea Proligands:
[0224] Urea proligands were prepared following a modified literature procedure.sup.3 in which the aniline (1 equiv) was dissolved in DCM and the solution was cooled to 0° C. Triphosgene (0.35 equiv) was added in one portion. The solution was stirred for five minutes after which N,N-diisopropylethylamine (2 equiv) was added and the cold bath removed. The solution was stirred for 1 hour and then piperidine (1 equiv) and a second portion of N,N-diisopropylethylamine (1 equiv) were added. The solution was stirred for an additional hour, and then diluted with 1M HCl. The organic phase was washed three times with 1M HCl dried over MgSO.sub.4, filtered, and concentrated by rotary evaporation.
Synthesis of 3-(2,6-dimethylphenyl)-1,1-diphenylurea
[0225] ##STR00027##
[0226] Prepared following the general procedure outlined above. Recrystallization provided the desired compound as a white solid (1.2 g, Unoptimized Synthesis): .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.42-7.38 (overlapping m, 8H, o-C.sub.6H.sub.5 and m-C.sub.6H.sub.5), 7.29-7.18 (m, 2H, p-C.sub.6H.sub.5), 7.05 (s, 3H, 2,6-Me.sub.2C.sub.6H.sub.3), 5.79 (NH), 2.27 (s, 6H, CH.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 153.94 (C═O), 142.72 (i-C.sub.6H.sub.5), 135.68 (o-C.sub.6H.sub.3), 134.56 (i-C.sub.6H.sub.3), 129.53 (m-C.sub.6H.sub.5), 128.12 (m-C.sub.6H.sub.3), 127.28 (o-C.sub.6H.sub.5), 126.85 (p-C.sub.6H), 126.40 (p-C.sub.6H.sub.3), 18.62 (CH.sub.3) ppm.
[0227] A .sup.1H NMR spectrum (300 MHz, CDCl.sub.3, 298 K) of 3-(2,6-dimethylphenyl)-1,1-diphenylurea is shown in
Synthesis of 3-(2,6-dimethylphenyl)-1-isopropyl-1-phenylurea
[0228] ##STR00028##
[0229] Prepared following the general procedure outlined above. Recrystallization provided the desired compound as a white solid (1.1 g, Unoptimized Synthesis): .sup.1H NMR (CDCl.sub.3, 400 MHz, 298 K): δ 7.61-7.28 (overlapping m, 5H, o,m,p-C.sub.6H.sub.5), 6.99 (s, 3H, C.sub.6H.sub.3), 5.24 (NH), 4.96 (hept, .sup.3J.sub.H-H=6.5 Hz, 1H, CH(CH.sub.3).sub.2), 2.19 (s, 6H, 2,6-(CH.sub.3).sub.2C.sub.6H.sub.3), 1.14 (d, .sup.3J.sub.H-H=6.2 Hz, 6H, CH(CH.sub.3).sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 101 MHz, 298 K): 154.62 (C═O), 138.17 (i-C.sub.6H.sub.5), 135.71 (o-C.sub.6H.sub.3), 135.18 (i-C.sub.6H.sub.3), 131.21 (m-C.sub.6H.sub.3), 129.83 (o-C.sub.6H.sub.5), 128.66 (p-C.sub.6H.sub.5), 127.94 (m-C.sub.6H.sub.3), 126.38 (p-C.sub.6H.sub.3), 46.58 (CH(CH.sub.3).sub.2), 21.65 (CH(CH.sub.3).sub.3), 18.47 (2,6-(CH.sub.3).sub.2C.sub.6H.sub.3) ppm.
[0230] A .sup.1H NMR spectrum (300 MHz, CDCl.sub.3 298 K) of 3-(2,6-dimethylphenyl)-1-isopropyl-1-phenylurea is shown in
Cyclic Ureate Ligands
Synthesis and Characterization of Cyclic Ureate Proligands
[0231] ##STR00029##
Synthesis of 1-cyclohexylimidazolidin-2-one (.SUP.Cy.LH)
[0232] ##STR00030##
[0233] A solution 2-chloroethyl isocyanate (1.11 g, 10.5 mmol) in THE (50 mL) was added dropwise to a stirring solution of cyclohexylamine (0.99 g, 10 mmol) in THF (20 mL) at room temperature. The resulting reaction mixture was treated with NaH (0.24 g, 10 mmol) under an inert atmosphere and stirred at room temperature overnight under an inert atmosphere. The mixture was treated with saturated NH.sub.4Cl (100 mL) and EtOAc (200 mL). The organic layer was separated and the aqueous layer was extracted with EtOAc (3×50 mL). The combined organic fractions were dried over Na.sub.2SO.sub.4 and concentrated under vacuum to form a colorless suspension in EtOAc. The reaction mixture was filtered and the resulting solid was dried to form the desired product. Yield (0.44 g, 27%). .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 5.41 (br s, 1H, NH), 3.77-3.58 (m, 1H, NCH), 3.43 (s, 4H, CH.sub.2CH.sub.2NH), 1.92-1.52 (m, 11H, HNCH.sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 162.52 (C═O), 40.71 (.sup.tBuNCH.sub.2), 51.15 (CH), 38.76 (HNCH.sub.2), 30.39 (.sup.CyCH.sub.2), 25.64 (.sup.CyCH.sub.2) ppm. HRMS (ESI): m/z calcd for C.sub.9H.sub.16N.sub.2ONa [M+Na.sup.+]: 191.1160. Found: 191.1159.
[0234]
Synthesis of 1-phenylimidazolidin-2-one (.SUP.Ph.LH)
[0235] ##STR00031##
[0236] A solution 2-chloroethyl isocyanate (1.05 g, 10 mmol) in THE (50 mL) was added dropwise to a stirring solution of phenylamine (0.93 g, 10 mmol) in THF (20 mL) at −20° C. The solution was brought to room temperature overnight. The resulting reaction mixture was treated with NaH (0.24 g, 10 mmol) under an inert atmosphere and stirred at room temperature overnight. The mixture was treated with saturated NH.sub.4Cl (100 mL) and EtOAc (200 mL). The organic layer was separated and the aqueous layer was extracted with EtOAc (3×50 mL). The combined organic fractions were dried over Na.sub.2SO.sub.4 and concentrated under vacuum to form a colorless suspension in EtOAc. The reaction mixture was filtered and the resulting solid was dried to form the desired product. Yield (0.42 g, 26%). .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.58 (d, 2H, J.sub.H-H=8.2 Hz, m-C.sub.6H.sub.5), 7.38-7.29 (m, 2H, o-CH.sub.5), 7.05 (t, 2H, J.sub.H-H=7.2 Hz, p-CH.sub.5), 4.00-3.84 (m, 2H, .sup.PhNCH.sub.2), 3.65-3.48 (m, 2H, HNCH.sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 160.27 (C═O), 140.18 (C.sub.6H.sub.5), 128.92 (C.sub.6H.sub.5), 122.83 (C.sub.6H.sub.5), 118.09 (C.sub.6H.sub.5), 45.49 (.sup.PhNCH.sub.2), 37.70 (HNCH.sub.2) ppm. HRMS (ESI): m/z calcd for C.sub.9H.sub.10N.sub.2ONa [M+Na.sup.+]: 185.0691. Found: 185.0691.
[0237]
Synthesis of 1-(tert-butyl)imidazolidin-2-one (.SUP.tBu.LH)
[0238] ##STR00032##
[0239] A solution 2-chloroethyl isocyanate (6.80 g, 64 mmol) in THF (50 mL) was added dropwise to a stirring solution of tertbutylamine (4.28 g, 58.5 mmol) in THF (20 mL) at −20° C. The solution was brought to room temperature overnight. The resulting reaction mixture was treated with NaH (6.8 g, 283 mmol) under an inert atmosphere and heated at 65° C. overnight under an inert atmosphere. The mixture was brought to dryness and treated with saturated NH.sub.4Cl (100 mL) and EtOAc (200 mL). The organic layer was separated and the aqueous layer was extracted with EtOAc (3×50 mL). The combined organic fractions were dried over Na.sub.2SO.sub.4 and brought to dryness under vacuum forming a yellow oil. Hexanes (5 mL) were then added resulting with the formation of a solid at the bottom of the round bottom flask. The mother liquor was removed by filtration. This process was repeated 3 more times and the combined hexane solutions (fraction 1) were stored at −30° C. overnight, while the solid (fraction 2) was also kept. Storing the combined hexane solutions (fraction 1) at low temperatures resulted in the formation of colorless crystals that were later filtered and dried in vacuo to afford 350 mg of pure product. The solid from fraction 2 was sublimed at 100° C. under vacuum to afford a waxy solid on the cold finger. The resulting waxy solid was washed with hexanes (2×4 mL) to afford 770 mg of pure product. Total yield: 1.12 g (13%). .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 4.37 (br s, 1H, NH), 3.49-3.40 (m, 2H, .sup.tBuNCH.sub.2), 3.33-3.23 (m, 2H, HNCH.sub.2), 1.36 (s, 9H, C(CH.sub.3).sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 163.15 (C═O), 52.96 (C(CH.sub.3).sub.3), 43.73 (.sup.tBuNCH.sub.2), 38.13 (HNCH.sub.2), 27.67 (C(CH.sub.3).sub.3) ppm. HRMS (ESI): m/z calcd for C.sub.7H.sub.14N.sub.2O [M+Na.sup.+]: 165.10039. Found: 165.1001. Anal. Calcd. for C.sub.7H.sub.14N.sub.2O: C, 59.12; H, 9.92; N, 19.70. Found: C, 59.12; H, 10.29; N, 19.71.
[0240]
Synthesis of Cyclic Ureate Ligand Salts
[0241] General Procedure for the Synthesis of Ligand Salts .sup.xLH (X=Me, Cy, pH, .sup.tBu):
[0242] NaN(SiMe.sub.3).sub.2 (1 equiv.) and the corresponding proteoligand (1 equiv.) were mixed in toluene (˜5 mL) and stirred overnight at room temperature. The volatiles were then removed at low pressure and the resulting solid was thoroughly stripped with hexanes (3×5 mL) and dried to give the sodium salt in moderate to quantitative yields as a colorless powder. The resulting ligand salts were used directly without further purification via storage in a glove box. Except in the case of .sup.DippLH, NMR characterization was precluded due to poor solubility in common NMR solvents (e.g. d.sub.6-benzene or d1-toluene).
Synthesis of Sodium 3-methyl-2-oxoimidazolidin-1-ide (.SUP.Me.L.SUP.−.Na.SUP.+.)
[0243] ##STR00033##
[0244] Prepared following the general procedure outlined above: .sup.MeLH (197 mg, 1.97 mmol) and NaN(SiMe.sub.3).sub.2 (361 mg, 1.97 mmol). Yield (163 mg, 68%).
Synthesis of Sodium 3-cyclohexyl-2-oxoimidazolidin-1-ide (.SUP.Cy.L.SUP.−.Na.SUP.+.)
[0245] ##STR00034##
[0246] Prepared following the general procedure outlined above: .sup.CyLH (100 mg, 0.59 mmol) and NaN(SiMe.sub.3).sub.2 (109 mg, 0.59 mmol). Yield (107 mg, 95%).
Synthesis of Sodium 2-oxo-3-phenylimidazolidin-1-ide (.SUP.Ph.L.SUP.−.Na.SUP.+.)
[0247] ##STR00035##
[0248] Prepared following the general procedure outlined above: .sup.PhLH (150 mg, 0.93 mmol) and NaN(SiMe.sub.3).sub.2 (170 mg, 0.93 mmol). Yield (140 mg, 82%).
Synthesis of Sodium 3-(tert-butyl)-2-oxoimidazolidin-1-ide (.SUP.tBu.L.SUP.−.Na.SUP.+.)
[0249] ##STR00036##
[0250] Prepared following the general procedure outlined above: .sup.tBuL.sup.−Na.sup.+ (230 mg, 1.62 mmol) and NaN(SiMe.sub.3).sub.2 (297 g, 1.62 mmol). Yield (265 mg, 99%).
Acyclic Ureate Ligands
Synthesis and Characterization of Proteoligands
[0251] General procedure for the synthesis of urea based proteoligands: Prepared following a modified literature procedure in which a chosen primary amine (1 equiv.) was dissolved in dichloromethane and the solution was cooled to 0° C. Triphosgene (0.35 equiv.) was added in portions as a solid. The solution was stirred for five minutes after which N,N-diisopropylethylamine DIPEA (3 equiv.) was added and the cold bath removed. The solution was stirred for 1 hour and then the appropriate amine (1 equiv.) and a second portion of DIPEA (1 equiv.) was added. The solution was stirred for an additional hour, and then diluted with 3M HCl. The organic phase was washed three times with 1M HCl dried over MgSO.sub.4, filtered, and concentrated by rotary evaporation to give the crude product.
Synthesis of 3-(2,6-dimethylphenyl)-1-methyl-1-(1-phenylethyl)urea
[0252] ##STR00037##
[0253] Prepared following the general procedure outlined above: 2,6-dimethylaniline (2.25 g, 18.5 mmol), triphosgene (1.81 g, 6.10 mmol), DIPEA (7.2 g, 55.5 mmol), N-methyl-1-phenylethan-1-amine (2.5 g, 18.5 mmol). Recrystallization from a concentrated ethyl acetate solution provided the desired compound as a white solid (3.48 g, 66.9%): .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.41-7.26 (overlapping m, 5H, o-C.sub.6H.sub.5 m-C.sub.6H.sub.5, and p-CeH.sub.5), 7.04 (s, 3H, m-C.sub.6H.sub.5, and p-C.sub.6H.sub.5), 5.86 (br s, 1H, NH), 5.64-5.57 (q, 1H, CHCH.sub.3), 2.79 (s, 3H, CH.sub.3), 2.19 (s, 6H, 2,6-(CH.sub.3).sub.2C.sub.6H.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 156.31 (C═O), 141.79, 135.58, 135.33, 128.64, 128.07, 127.28, 126.88, 126.34, 52.80, 29.53, 18.43, 17.02 ppm. HRMS (ESI): m/z calcd for C.sub.18H.sub.23N.sub.2O [M+H.sup.+]: 283.1810. Found: 283.1809.
[0254]
Synthesis of 3-(2,6-dimethylphenyl)-1-isopropyl-1-phenylurea
[0255] ##STR00038##
[0256] Prepared following the general procedure outlined above: 2,6-dimethylaniline (1.5 g, 20.5 mmol), triphosgene (2.02 g, 7.41 mmol), DIPEA (7.95 g, 61.5 mmol), N-isopropylaniline (2.5 g, 20.5 mmol). Recrystallization from a concentrated ethyl acetate solution provided the desired compound as a white solid (3.20 g, 65%): .sup.1H NMR (CDCl.sub.3, 400 MHz, 298 K): δ 7.05 (s, 3H, o,m,p-C.sub.6H.sub.5), 5.69 (br s, 1H, NH), 4.56-4.49 (m, 1H, CH(CH.sub.3).sub.2), 2.86 (s, 3H, CH.sub.3), 2.24 (s, 6H, 2,6-(CH.sub.3).sub.2C.sub.6H.sub.3), 1.17 (d, J.sub.H-H=1.7 Hz, 6H, CH(CH.sub.3).sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 101 MHz, 298 K): δ 156.00 (C═O), 135.70, 135.57, 128.20, 126.40, 45.89, 27.45, 20.21, 18.56 ppm. HRMS (ESI): m/z calcd for C.sub.13H.sub.21N.sub.2O [M+H.sup.+]: 221.1654. Found: 221.1656.
[0257]
Synthesis of 1-benzhydryl-3-(2,6-dimethylphenyl)-1-methylurea
[0258] ##STR00039##
[0259] Prepared following the general procedure outlined above: 2,6-dimethylaniline (307 mg, 2.53 mmol), triphosgene (250.2 mg, 0.843 mmol), DIPEA (981 mg, 7.59 mmol), N-methyl-1,1-diphenylmethanamine (500 mg, 2.53 mmol). Recrystallization from a concentrated ethyl acetate solution provided the desired compound as a white solid (750 mg, 86%): .sup.1H NMR (CDCl.sub.3, 400 MHz, 298 K): δ 7.41-7.27 (overlapping m, 10H, o,m,p-C.sub.6H.sub.5), 7.04 (s, 3H, m,p-C.sub.6H.sub.5), 6.70 (s, 1H, NHCH), 5.78 (br s, 1H, NH), 2.88 (s, 3H, CH.sub.3), 2.16 (s, 6H, 2,6-(CH.sub.3).sub.2C.sub.6H.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 101 MHz, 298 K): δ 156.57 (C═O), 139.66, 135.47, 135.30, 128.80, 128.77, 128.25, 127.80, 126.49, 63.30, 32.05, 28.48 ppm. HRMS (ESI): m/z calcd for C.sub.23H.sub.25N.sub.2O [M+H.sup.+]: 345.1967 Found: 345.1964.
[0260]
Synthesis of 3-(2,6-diisopropylphenyl)-1-methyl-1-(1-phenylethyl)urea
[0261] ##STR00040##
[0262] Prepared following the general procedure outlined above: 2,6-dimethylaniline (1.32 g, 7.40 mmol), triphosgene (724 mg, 2.44 mmol), DIPEA (2.87 g, 22.2 mmol), N-methyl-1,1-diphenylmethanamine (1.0 g, 7.40 mmol). Recrystallization from a concentrated ethyl acetate solution provided the desired compound as a white solid (1.81 g, 72.3%): .sup.1H NMR (CDCl.sub.3, 400 MHz, 298 K): δ 7.51-7.50 (overlapping m, 4H), 7.45-7.39 (overlapping m, 2H), 7.37-7.35 (m, 1H), 7.28 (m, 1H), 5.78-5.72 (overlapping m, 2H), 3.22-3.12 (m, 2H, CH(CH.sub.3).sub.2), 3.00 (s, 3H, CH.sub.3), 1.72 (s, 3H, CH.sub.3), 1.31 (s, 12H, CH(CH.sub.3).sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 101 MHz, 298 K): δ 157.22 (C═O), 146.52, 142.12, 132.80, 128.73, 127.63, 127.41, 126.95, 123.36, 52.99, 29.82, 28.79, 23.81 ppm. HRMS (ESI): m/z calcd for C.sub.22H.sub.31N.sub.2O [M+H.sup.+]: 339.2437. Found: 339.2444.
[0263]
Synthesis of Ta(CH.SUB.2.SiMe.SUB.3.).SUB.3.Br.SUB.2
[0264] A solution of Zn(CH.sub.2SiMe.sub.3).sub.2 (0.64 g, 2.67 mmol) in hexanes (20 mL) was added to a suspension of TaBr.sub.5 (1.00 g, 1.72 mmol) in hexanes (10 mL). The reaction mixture was stirred at room temperature overnight forming a colorless precipitate. The following day, the solution was filtered and concentrated in vacuo to afford the formation of the title product as yellow powder. Yield (0.73 g, 71%). .sup.1H NMR (toluene-de, 300 MHz, 298 K): δ 2.11 (s, 6H, CH.sub.2), 0.29 (s, 27H, SiCH.sub.3) ppm.
3.3 Ligand Salts
General Procedure for the Synthesis of Ligand Salts
[0265] NaN(SiMe.sub.3).sub.2 (1 equiv.) was added in portions to a suspension of the corresponding proteo-ligand (1 equiv.) in Et.sub.2O (˜10 mL) and stirred overnight at room temperature. The volatiles were then removed at low pressure and the resulting solid was thoroughly washed with hexanes (3×5 mL) and dried to give the sodium salt as a colorless powder. Salts were used directly without further characterization.
##STR00041##
Synthesis and Characterization of Tantalum Based Ureate Complexes
[0266] ##STR00042##
[0267]
Synthesis of .SUP.tBu.LTa(CH.SUB.2.SiMe.SUB.3.).SUB.3.Cl
[0268] ##STR00043##
[0269] A suspension of .sup.tBuL.sup.−Na.sup.+ (71 mg, 0.43 mmol) in toluene (3 mL) was added dropwise at room temperature to a solution of Ta(CH.sub.2SiMe.sub.3)Cl.sub.2 (200 mg, 0.39 mmol) in toluene (3 mL). The reaction mixture was stirred for 30 min. The volatiles were then removed in vacuo and the title complex was extracted with hexanes (3×5 mL) and filtered over celite. The resulting organic solution was concentrated to approx. 3 mL and stored in a freezer at −30° C. A large crop of crystals were formed overnight which were further dried affording the title compound as pale yellow crystals. Yield (150 mg, 62%). .sup.1H NMR (benzene-d.sub.6, 300 MHz, 298 K): δ 3.36-3.23 (m, 2H, NCH.sub.2), 2.75-2.62 (m, 2H, NCH.sub.2), 1.57 (s, 6H, CH.sub.2SiMe.sub.3), 1.06 (s, 9H, NC(CH.sub.3).sub.3, 0.36 (s, 27H, SiCH.sub.3) ppm. .sup.13C NMR (benzene-d.sub.6, 75 MHz, 298 K): δ 171.36 (C═O), 90.19 (CH.sub.2SiMe.sub.3), 53.68 (NC(CH.sub.3).sub.3), 45.38 (NCH.sub.2), 44.41 (NCH.sub.2), 27.96 (NC(CH.sub.3).sub.3), 2.79 (SiCH.sub.3) ppm. LRMS (ESI): m/z: 531 (M−CH.sub.2SiMe.sub.3−H.sup.+), 443 (M−2CH.sub.2SiMe.sub.3−2H.sup.+). Anal. Calcd. for C.sub.19H.sub.47ClN.sub.2OSi.sub.3Ta: C, 36.79; H, 7.64; N, 4.52. Found: C, 36.44; H, 7.69; N, 4.59.
[0270]
[0271]
Synthesis of .SUP.tBu.LTa(CH.SUB.2.SiMe.SUB.3.).SUB.3.Br
[0272] ##STR00044##
[0273] A suspension of .sup.tBuL.sup.−Na.sup.+ (30 mg, 0.19 mmol) in toluene (3 mL) was added dropwise at room temperature to a solution of Ta(CH.sub.2SiMe.sub.3)Cl.sub.2 (106 mg, 0.18 mmol) in toluene (3 mL). The reaction mixture was stirred for 30 min. The volatiles were then removed in vacuo and the title complex was extracted with hexanes (3×5 mL) and filtered over celite. The resulting organic solution was concentrated to approx. 3 mL and stored in a freezer at −30° C. A large crop of crystals were formed overnight which were further dried affording the title compound as pale yellow crystals. Yield (35 mg, 30%). .sup.1H NMR (benzene-d.sub.6, 400 MHz, 298 K): δ 3.31-3.24 (m, 2H, NCH.sub.2), 2.72-2.65 (m, 2H, NCH.sub.2), 1.62 (s, 6H, CH.sub.2SiMe.sub.3), 1.05 (s, 9H, NC(CH.sub.3).sub.3, 0.37 (s, 27H, SiCH.sub.3) ppm. .sup.13C NMR (benzene-d.sub.6, 75 MHz, 298 K): δ 171.18 (C═O), 94.33 (CH.sub.2SiMe.sub.3), 53.78 (NC(CH.sub.3).sub.3), 45.34 (NCH.sub.2), 44.16 (NCH.sub.2), 27.96 (NC(CH.sub.3).sub.3), 2.91 (SiCH.sub.3) ppm.
[0274]
[0275]
Synthesis and Characterization of Tantalum Based Ureate Complexes
Synthesis of LTa(CH.SUB.2.SiMe.SUB.3.).SUB.3.Cl
[0276] ##STR00045##
[0277] A suspension of L.sup.−Na.sup.+ (206 mg, 0.81 mmol) in toluene (5 mL) was added dropwise at room temperature to a solution of Ta(CH.sub.2SiMe.sub.3)Cl.sub.2 (378 mg, 0.736 mmol) in toluene (6 mL). The reaction mixture was stirred for 30 min. The volatiles were then removed in vacuo and the title complex was extracted with hexanes (3×5 mL) and filtered over celite. The resulting organic solution was concentrated to approx. 3 mL and stored in a freezer at −30° C. Over a week period, a large amount of solid precipitated. The mixture was then filtered and the resulting solid was dried in vacuo to form the desired complex. Yield (370 mg, 71%). .sup.1H NMR (benzene-d.sub.6, 300 MHz, 298 K): δ 6.92-6.80 (m, 3H, C.sub.6H.sub.3), 3.52-3.85 (m, 2H, CH.sub.2), 2.21 (s, 6H, CH.sub.2SiMe.sub.3), 1.41 (s, 6H, CH.sub.3), 0.39 (s, 27H, SiCH.sub.3) ppm.
[0278]
3.4 Hydroaminoalkylation Reaction:
General Procedure for Hydroaminoalkylation Reaction:
[0279] Solid tantalum precursor (0.0025 mmol) was weighed into a vial, followed by addition of the chosen ligand salt (0.025 mmol) d.sub.6-toluene (0.3 g) was added, and the resultant mixture was left for 15 minutes. A chosen amine substrate was then added (0.5 mmol), followed by the alkene (0.5 mmol). The resultant reaction mixture was transferred into a J. Young NMR tube and the vial was rinsed with an additional 0.2 g of d.sub.8-toluene. An initial .sup.1H NMR spectrum was recorded and the sample was added to a pre-heated oil bath. All conversion values were determined by .sup.1H NMR spectroscopy. After removal of all reaction solvent, pentane was added to the reaction mixture and a white precipitate was formed instantaneously. Residual tantalum salts and proteo-ligands were then removed by filtering the pentane solution at −80° C. Unreacted amine or alkene starting materials were removed at 40° C. under low pressure. In all cases, .sup.1H NMR spectroscopy still showed the presence of proteo-ligands in low amounts (2-4%), which can be entirely removed by column chromatography. N-(2-propylhexyl)aniline and N-(2-ethylpentyl)aniline showed signs of decomposition while heated under vacuum, and therefore must be purified by column chromatography.
General Procedure for Post-Polymerization Amination of Polyolefins.
[0280] All experiments were performed in the presence of Ta complex .sup.tBuLTa(CH.sub.2SiMe.sub.3).sub.3Cl (Table 12), which could be used either in an isolated form or formed in situ. Based on NMR experiments, the initial polyolefins had a molecular weight range between 350-3500 g/mol. The precatalyst and the internal standard (1,3,5-trimethoxybenzene) were weighed in separate vials. In a different vial, the polyolefin (in a stock solution or neat) was mixed with the corresponding amount of the amine. Toluene-d8 was then added to the first vials and the combined solution of all mentioned vials was transferred to a J-young NMR tube. The vials were further rinsed with 200 mg of toluene-d8 and transferred to the NMR tube. An initial 1H-NMR spectrum was recorded prior to heating the sample. The NMR tube was then added to a preheated oil bath (110° C.—for N-methylaniline and N-methylcyclohexylamine; 145° C.—for N-methylbutylamine) for the corresponding amount of time. The polymers derived from Sample 1, vinyl-terminated atactic polypropylene (“vt aPP”) having a molecular weight of about 300 g/mol and supplied neat and corresponding to entries 1 to 6 in Table 12, were purified via column chromatography. The polymers derived from Sample 2, vinyl-terminated atactic polypropylene (“vt aPP”; supplied as a stock solution in toluene and corresponding to entries 7 to 12 in Table 12) having a molecular weight of about 1,500 to about 2,000 g/mol, and Sample 3, vinyl-terminated copolymer poly(ethylene-co-propylene) (vt EP) having a molecular weight of approximately 3500 g/mol and corresponding to entries 12 to 14 in Table 12, were purified by dissolving the sample in dichloromethane and precipitating the desired product with methanol. This process was repeated 3 times. All reactions were performed on a 100 mg scale corresponding to the polyolefin.
N-(2-methyloctyl)aniline
[0281] ##STR00046##
[0282] N-methylaniline (54 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 88%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.24-7.16 (m, 2H, bum-C.sub.6H.sub.5), 6.75-6.67 (m, 1H, p-C.sub.6H.sub.5), 6.67-6.60 (m, 2H, o-C.sub.6H.sub.5), 3.69 (br s, 1H, NH), 3.08 (dd, J.sub.H-H=12.8, 5.8 Hz, 1H, NC(H)H), 2.91 (dd, J.sub.H-H=12.2, 7.3 Hz, 1H, NC(H)H), 1.86-1.68 (m, 1H, CH), 1.53-1.14 (overlapping m, 10H, CH.sub.2), 1.00 (d, J.sub.H-H=6.6 Hz, 3H, CHCH.sub.3), 0.97-0.89 (t, J.sub.H-H=6.1 Hz, 3H, CH.sub.2CH.sub.3) ppm. The chemical shifts for the title compound match those reported by Hartwig et al.
N-(cyclooctylmethyl)aniline
[0283] ##STR00047##
[0284] N-methylaniline (54 mg, 0.5 mmol), cyclooctene (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 6 h. Yield 83%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.20 (dd, J.sub.H-H=8.5, 7.4 Hz, 2H, m-C.sub.6H.sub.5), 6.70 (t, J.sub.H-H=6.7 Hz, 1H, p-C.sub.6H.sub.5), 6.62 (dd, J.sub.H-H=8.5, 0.9 Hz, 2H, o-C.sub.6H.sub.4), 3.71 (br s, 1H, NH), 2.08 (d, J.sub.H-H=6.8 Hz, NCH.sub.2), 1.92-1.27 (overlapping m, 13H, CH.sub.2 and CH) ppm.
4-methoxy-N-(2-methyloctyl)aniline
[0285] ##STR00048##
[0286] 4-methoxy-N-methylaniline (96 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 77%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 6.84-6.74 (m, 2H, m-C.sub.6H.sub.4), 6.63-6.55 (m, 2H, o-C.sub.6H.sub.4), 3.76 (s, 3H, OCH.sub.3), 3.38 (br s, 1H, NH), 3.02 (dd, J.sub.H-H=5.8, 12.1 Hz, 1H, NC(H)H), 3.02 (dd, J.sub.H-H=7.8, 12.1 Hz, 1H, NC(H)H), 1.82-1.64 (m, 1H, CH), 1.55-1.05 (m, 10H, CH.sub.2), 0.98 (d, J.sub.H-H=6.6 Hz, 3H, CHCH.sub.3), 0.91 (t, J.sub.H-H=6.7 Hz, 3H, CH.sub.2CH.sub.3) ppm. The chemical shifts for the title compound match those previously reported in the literature.
4-bromo-N-(2-methyloctyl)aniline
[0287] ##STR00049##
[0288] 4-bromo-N-methylaniline (93 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 86%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.23 (d, J.sub.H-H=8.7 Hz, 2H, m-C.sub.6H.sub.4), 6.48 (d, J.sub.H-H=8.9 Hz, 2H, o-CH.sub.4), 3.92 (br s, 1H, NH), 3.01 (dd, J.sub.H-H=5.9, 12.2 Hz, 1H, NC(H)H), 2.84 (dd, J.sub.H-H=7.1, 12.1 Hz, 1H, NC(H)H), 1.78-1.65 (m, 1H, CH), 1.51-1.08 (m, 10H, CH.sub.2), 0.96 (d, J.sub.H-H=6.6 Hz, 3H, CHCH.sub.3), 0.89 (t, J.sub.H-H=6.9 Hz, 3H, CH.sub.2CH.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 148.51 (i-C.sub.6H.sub.4), 129.34 (m-C.sub.6H.sub.4), 117.24 (p-C.sub.6H.sub.4), 112.87 (o-C.sub.6H.sub.4), 48.11, 47.99, 37.45, 37.28, 36.79, 36.56, 29.68, 27.37, 27.00, 26.11, 25.95, 25.04, 14.94 (CH.sub.3), 14.48 (CH.sub.3) ppm.
[0289]
4-bromo-N-(cyclooctylmethyl)aniline
[0290] ##STR00050##
[0291] 4-bromo-N-methylaniline (93 mg, 0.5 mmol), cyclooctene (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 6 h. Yield 95%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.25 (d, J.sub.H-H=8.8 Hz, m-C.sub.6H.sub.4), 6.47 (d, J.sub.H-H=8.8 Hz, o-C.sub.6H.sub.4), 3.75 (br s, 1H, NH), 2.90 (d, J.sub.H-H=6.8 Hz, NCH.sub.2), 1.86-1.24 (overlapping m, 13H, CH and CH.sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 147.65 (i-C.sub.6H.sub.4), 131.95 (m-C.sub.6H.sub.4), 114.25 (o-C.sub.6H.sub.4), 108.40 (p-C.sub.6H.sub.4), 51.21 (NCH.sub.2), 37.33 (CH.sub.2), 30.67 (CH.sub.2), 27.13 (CH.sub.2), 26.41 (CH.sub.2), 25.58 (CH.sub.2) ppm.
[0292]
4-chloro-N-(2-methyloctyl)aniline
[0293] ##STR00051##
[0294] 4-chloro-N-methylaniline (71 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 90%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.12 (d, J.sub.H-H=8.8 Hz, 2H, m-C.sub.6H.sub.5), 6.52 (d, J.sub.H-H=8.8 Hz, 2H, o-CH.sub.5), 3.78 (br s, 1H, NH), 3.02 (dd, J.sub.H-H=5.9, 12.2 Hz, 1H, NC(H)H), 2.86 (dd, J.sub.H-H=7.2, 12.2 Hz, 1H, NC(H)H), 1.82-1.65 (m, 1H, CH), 1.51-1.09 (m, 10H, CH.sub.2), 0.97 (d, J.sub.H-H=6.6 Hz, 3H, CHCH.sub.3), 0.91 (t, J.sub.H-H=6.8 Hz, 3H, CH.sub.2CH.sub.3) ppm. The chemical shifts for the title compound match those previously reported in the literature.
4-chloro-N-(cyclooctylmethyl)aniline
[0295] ##STR00052##
[0296] 4-chloro-N-methylaniline (71 mg, 0.5 mmol), cyclooctene (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 6 h. Yield 93%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.10 (d, J.sub.H-H=8.8 Hz, m-C.sub.6H.sub.4), 6.51 (d, J.sub.H-H=8.8 Hz, o-C.sub.6H.sub.4), 3.71 (br s, 1H, NH), 2.90 (d, J.sub.H-H=6.8 Hz, NCH.sub.2), 1.87-1.21 (overlapping m, 13H, CH and CH.sub.2). ppm. .sup.3C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 147.29 (i-C.sub.6H.sub.4), 129.10 (m-C.sub.6H.sub.4), 121.41 (p-C.sub.6H.sub.4), 113.73 (o-C.sub.6H.sub.4), 51.32 (NCH.sub.2), 37.38 (CH.sub.2), 30.70 (CH.sub.2), 27.14 (CH.sub.2), 26.43 (CH.sub.2), 25.59 (CH.sub.2) ppm.
[0297]
4-fluoro-N-(2-methyloctyl)aniline
[0298] ##STR00053##
[0299] 4-fluoro-N-methylaniline (63 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 88%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 6.89 (t, J.sub.H-H=8.8 Hz, 2H, m-C.sub.6H.sub.5), 6.59-6.50 (m, 2H, o-C.sub.6H.sub.5), 3.57 (br s, 1H, NH), 3.02 (dd, J.sub.H-H=5.9, 12.1 Hz, 1H, NC(H)H), 2.85 (dd, J.sub.H-H=7.2, 12.0 Hz, 1H, NC(H)H), 1.82-1.65 (m, 1H, CH), 1.51-1.11 (m, 10H, CH.sub.2), 0.98 (d, J.sub.H-H=6.7 Hz, 3H, CHCH.sub.3), 0.91 (t, J.sub.H-H=6.9 Hz, 3H, CH.sub.2CH.sub.3) ppm.
N-(cyclooctylmethyl)-4-fluoroaniline
[0300] ##STR00054##
[0301] 4-fluoro-N-methylaniline (63 mg, 0.5 mmol), cyclooctene (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 6 h. Yield 88%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 6.89 (t, J.sub.H-H=8.7 Hz, 2H, m-CH.sub.4), 6.57-6.49 (m, 2H, o-C.sub.6H.sub.4), 3.58 (br s, 1H, NH), 2.90 (d, J.sub.H-H=6.7 Hz, 2H, NCH.sub.2), 1.88-1.22 (overlapping m, 13H, CH and CH.sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 100 MHz, 298 K): δ 155.68 (d, J.sub.C-F=234.2 Hz, p-C.sub.6H.sub.4), 145.05 (i-C.sub.6H.sub.4), 115.66 (d, J.sub.C-F=22.2 Hz, m-C.sub.6H.sub.4), 113.49 (d, J.sub.C-F=7.3 Hz, o-C.sub.6H.sub.4), 51.99 (NCH.sub.2), 37.41 (CH.sub.2), 30.72 (CH.sub.2), 27.15 (CH.sub.2), 26.43 (CH.sub.2), 25.60 (CH.sub.2) ppm. .sup.79F NMR (CDCl.sub.3, 282.4 MHz, 298 K): δ −129.00 (tt, J.sub.H-F=4.5 Hz, 1F, C.sub.6H.sub.4F) ppm.
[0302]
N-(2-methyloctyl)-4-(trifluoromethoxy)aniline
[0303] ##STR00055##
[0304] N-methyl-4-(trifluoromethoxy)aniline (96 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 3 h. Yield 92%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.03 (d, J.sub.H-H=8.2 Hz, 2H, m-C.sub.6H.sub.4), 6.59-6.50 (m, 2H, o-C.sub.6H.sub.4), 3.80 (br s, 1H, NH), 3.03 (dd, J.sub.H-H=5.9, 12.2 Hz, 1H, NC(H)H), 2.85 (dd, J.sub.H-H=7.3, 12.2 Hz, 1H, NC(H)H), 1.82-1.64 (m, 1H, CH), 1.51-1.09 (m, 10H, CH.sub.2), 0.97 (d, J.sub.H-H=6.7 Hz, 3H, CHCH.sub.3), 0.90 (t, J.sub.H-H=6.9 Hz, 3H, CH.sub.2CH.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 300 MHz, 298 K): δ 147.51 (i-C.sub.6H.sub.5), 122.53 (C.sub.6H.sub.5), 112.89 (C.sub.6H.sub.5), 50.67 (NCH.sub.2), 34.90, 33.02, 32.00, 29.73, 27.07, 22.81, 18.17 (CH.sub.3), 14.23 (CH.sub.3) ppm. .sup.19F NMR (CDCl.sub.3, 282.4 MHz, 298 K): δ −58.81 (s, 3F, CF.sub.3) ppm.
[0305]
N-(cyclooctylmethyl)-4-(trifluoromethoxy)aniline
[0306] ##STR00056##
[0307] N-methyl-4-(trifluoromethoxy)aniline (96 mg, 0.5 mmol), cyclooctene (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 6 h. Yield 85%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.03 (d, J.sub.H-H=9.0 Hz, 2H, m-C.sub.GH.sub.4), 6.59-6.50 (m, 2H, o-CH), 3.77 (br s, 1H, NH), 0.2.92 (d, J.sub.H-H=6.5 Hz, 1H, NCH.sub.2), 1.89-1.21 (overlapping m, 13H, CH and CH.sub.2) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 147.55 (i-C.sub.6H.sub.4), 122.51 (C.sub.6H.sub.4), 112.81 (C.sub.6H.sub.4), 51.43 (NCH.sub.2), 37.48, 30.73, 27.17, 26.44, 25.61 ppm. .sup.19F NMR (CDCl.sub.3, 282.4 MHz, 298 K): δ −58.79 (s, 3F, CF.sub.3) ppm.
[0308]
N-(2-methyloctyl)benzo[d][1,3]dioxol-5-amine
[0309] ##STR00057##
[0310] N-methylbenzo[d][1,3]dioxol-5-amine (76 mg, 0.5 mmol), 1-octene (0.056 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 85%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 6.66 (d, J.sub.H-H=8.3 Hz, 2H, m-C.sub.6H.sub.3), 6.25 (d, J.sub.H-H=8.3 Hz, 1H, o-C.sub.6H.sub.3), 6.04 (dd, J.sub.H-H=2.3, 8.3 Hz, 1H, o-C.sub.6H.sub.3), 5.85 (s, 2H, OCH.sub.2), 3.48 (br s, 1H, NH), 2.99 (dd, J.sub.H-H=5.9, 12.0 Hz, 1H, NC(H)H), 2.84 (dd, J.sub.H-H=5.0, 12.2 Hz, 1H, NC(H)H), 1.81-1.62 (m, 1H, CH), 1.50-1.08 (m, 10H, CH.sub.2), 0.97 (d, J.sub.H-H=6.7 Hz, 3H, CHCH.sub.3), 0.91 (t, J.sub.H-H=7.1 Hz, 3H, CH.sub.2CH.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 148.46 (i-C.sub.6H.sub.3), 144.64 (m-C.sub.6H.sub.3), 139.40 (p-C.sub.6H.sub.3), 108.75 (m-C.sub.6H.sub.3), 104.34 (OCH.sub.2), 100.62 (o-C.sub.6H.sub.3), 95.90 (o-C.sub.6H.sub.3), 51.54, 34.94, 33.03, 32.00, 29.74, 27.06, 22.80, 18.20 (CH.sub.3), 14.23 (CH.sub.3) ppm.
[0311]
N-(4-((tert-butyldimethylsilyl)oxy)-2-methylbutyl)aniline
[0312] ##STR00058##
[0313] N-methylaniline (54 mg, 0.5 mmol), (but-3-en-1-yloxy)(tert-butyl)dimethylsilane (93 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 75%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.20 (t, .sup.3J.sub.H-H=7.8, 2H, m-C.sub.6H.sub.4), 6.70 (td, .sup.3J.sub.H-H=0.9, 7.3, 1H, p-CH.sub.4), 6.63 (d, .sup.3J.sub.H-H=8.5, 2H, o-CH.sub.4), 3.85 (br s, 1H, NH), 3.83-3.64 (m, 2H, OCH.sub.2), 3.10 (dd, J.sub.H-H=6.3, 12.2 Hz, 1H, NC(H)H), 2.97 (dd, J.sub.H-H=6.9, 12.2 Hz, 1H, NC(H)H), 1.97 (oct, J.sub.H-H=6.7 Hz, 1H, OCH.sub.2C(H)H), 1.76-1.61 (m, 1H, CHCH.sub.3), 1.53-1.39 (m, 1H, OCH.sub.2C(H)H), 0.95 (d, J.sub.H-H=1.3 Hz, 9H, SiC(CH.sub.3).sub.3), 0.10 (d, J.sub.H-H=1.1 Hz, 6H, SiCH.sub.3) ppm. .sup.13C NMR (CDCl.sub.3, 75 MHz, 298 K): δ 148.71 (i-C.sub.6H.sub.5), 129.33 (m-C.sub.6H.sub.6), 117.00 (p-C.sub.6H.sub.5), 112.74 (o-C.sub.6H.sub.5), 77.16 (OCH.sub.2), 61.20 (NCH.sub.2), 50.43 (OCH.sub.2CH.sub.2), 37.94, 29.98, 26.10 (SiC(CH.sub.3).sub.3), 18.44 (CHCH.sub.3), −5.18 (SiCH.sub.3) ppm.
[0314]
N-(2-cyclohexylpropyl)aniline
[0315] ##STR00059##
[0316] N-methylaniline (54 mg, 0.5 mmol), vinylcyclohexane (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 86%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.25-7.17 (m, 2H, m-C.sub.6H.sub.4), 6.79-6.69 (m, 1H, p-CeH.sub.4), 6.69-6.63 (m, 2H, o-C.sub.6H.sub.4) 3.87 (br s, 1H, NH), 3.20 (dd, J.sub.H-H=5.5, 12.1 Hz, 1H, NC(H)H), 2.93 (dd, J.sub.H-H=7.9, 12.1 Hz, 1H, NC(H)H), 1.87-1.60 (overlapping m, 6H, CH and CH.sub.2.sup.Cy), 1.47-1.04 (m, 6H, CH.sub.2.sup.Cy), 0.99 (d, J.sub.H-H=6.9 Hz, 3H, CHCH.sub.3) ppm.
N-((1-methylcyclohexyl)methyl)aniline
[0317] ##STR00060##
[0318] N-methylaniline (54 mg, 0.5 mmol), vinylcyclohexane (48 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 3 h. Yield 99%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.30-7.21 (m, 2H, m-C.sub.6H.sub.5), 6.82-6.66 (overlapping m, 3H, o-C.sub.6H.sub.5 and p-CeH.sub.5), 3.68 (br s, 1H, NH), 3.03 (s, 2H, NCH.sub.2), 1.69-1.33 (overlapping m, 10H, CH.sub.2.sup.Cy), 1.08 (s, 3H, CH.sub.3) ppm.
N-(2-(cyclohex-3-en-1-yl)propyl)aniline
[0319] ##STR00061##
[0320] N-methylaniline (54 mg, 0.5 mmol), vinylcyclohexane (55 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 98%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.28-7.17 (m, 2H, m-C.sub.6H.sub.5), 6.75 (t, J.sub.H-H=6.8 Hz, 1H, m-C.sub.6H.sub.5), 6.67 (d, J.sub.H-H=7.8 Hz, 1H, o-C.sub.6H.sub.5), 5.75 (s, 2H, CH═CH.sub.2), 3.89 (br s, 1H, NH), 3.30-3.18 (m, 1H, NC(H)H), 3.05-2.92 (m, 1H, NC(H)H), 2.25-1.24 (overlapping m, 8H, CHCH.sub.3, CH.sub.2CH, and CH.sub.2), 1.07-0.98 (m, 3H, CH.sub.3) ppm. The chemical shifts for the title compound match those reported in the literature.
N-(2-methyl-4-phenylbutyl)aniline
[0321] ##STR00062##
[0322] N-methylaniline (54 mg, 0.5 mmol), 4-phenyl-1-butene (66 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 3 h. Yield 87%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.38-7.28 (m, 2H, m-C.sub.6H.sub.5), 7.27-7.15 (overlapping m, 5H, m-NC.sub.6H.sub.5, o-C.sub.6H.sub.5, and p-C.sub.6H.sub.5), 6.72 (t, J.sub.H-H=7.1 Hz, 1H, p-NCH.sub.5), 6.62 (d, J.sub.H-H=7.9 Hz, 2H, o-NC.sub.6H.sub.5), 3.69 (br s, 1H, NH), 3.13 (dd, J.sub.H-H=5.8, 12.3 Hz, 1H, NC(H)H), 2.97 (dd, J.sub.H-H=6.9, 12.3 Hz, 1H, NC(H)H), 2.84-2.57 (m, 2H, C.sub.6H.sub.5CH.sub.2), 1.92-1.75 (m, 2H, C.sub.6H.sub.5CH.sub.2CH.sub.2), 1.64-1.47 (m, 1H, CHCH.sub.3), 1.08 (d, J.sub.H-H=6.6 Hz, 2H, CHCH.sub.3) ppm. The chemical shifts for the title compound match those reported in the literature.
N-(2-(4-chlorophenyl)propyl)aniline
[0323] ##STR00063##
[0324] N-methylaniline (54 mg, 0.5 mmol), 4-chlorostyrene (70 g, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 98%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.31 (d, J.sub.H-H=8.4 Hz, 2H, m-C.sub.6H.sub.4Cl), 7.23-7.14 (overlapping m, 4H, m-C.sub.6H.sub.4Cl and o-C.sub.6H.sub.5), 6.72 (t, J.sub.H-H=7.2 Hz, 1H, p-C.sub.6H.sub.5), 6.59 (d, J.sub.H-H=8.5 Hz, 2H, o-CH.sub.5), 3.59 (br s, 1H, NH), 3.35 (dd, J.sub.H-H=6.1, 12.5 Hz, 1H, NC(H)H), 3.22 (dd, J.sub.H-H=8.2, 12.4 Hz, 1H, NC(H)H), 3.13-2.99 (m, 1H, CHCH.sub.3), 1.33 (d, J.sub.H-H=6.9 Hz, 3H, CHCH.sub.3) ppm.
N-(2-(2-bromophenyl)propyl)aniline (A) and N-(3-(2-bromophenyl)propyl)aniline (B)
[0325] ##STR00064##
[0326] N-methylaniline (54 mg, 0.5 mmol), 2-bromostyrene (92 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L4 (8 mg, 0.025 mmol). Reaction time: 2 h. Yield 65%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): Product is a combination of linear and branched HAA products (˜9:1), additional spectra are required for full peak assignments.
[0327]
N-(2-methyl-3-phenylpropyl)aniline (A) and N-(2-phenylbutyl)aniline (B)
[0328] ##STR00065##
[0329] N-methylaniline (54 mg, 0.5 mmol), cis/trans-β-methylstyrene (60 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 48 h. Yield 78%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 5 7.42-7.12 (overlapping m, 14H, m-C.sub.6H.sub.5.sup.A, m-NC.sub.6H.sub.5.sup.A, o,p-C.sub.6H.sub.5.sup.A, o,m,p-C.sub.6H.sub.5.sup.B, and m-NC.sub.6H.sub.5.sup.B), 6.79-6.52 (overlapping m, 6H, p-NC.sub.6H.sub.5.sup.A, o-NC.sub.6H.sub.5.sup.A, p-NC.sub.6H.sub.5.sup.B, and o-NC.sub.6H.sub.5.sup.B), 3.69 (br s, 1H, NH.sup.A), 3.60-3.38 (overlapping m, 2H, NH.sup.B and NC(H)H.sup.B), 3.30-3.19 (m, 1H, NC(H)H.sup.B), 3.13 (dd, J.sub.H-H=6.0, 12.4 Hz, 1H, NC(H)H.sup.A), 2.98 (dd, J.sub.H-H=6.9, 12.3 Hz, 1H, NC(H)H.sup.A), 2.87-2.75 (m, 1H, C.sub.6H.sub.5CH.sup.B), 2.79 (dd, J.sub.H-H=6.3, 13.4 Hz, 1H, C.sub.6H.sub.5C(H)H.sup.A), 2.53 (dd, J.sub.H-H=6.3, 13.4 Hz, 1H, C.sub.6H.sub.5C(H)H.sup.A), 2.18-2.03 (m, 1H, CHCH.sub.3.sup.A), 1.92-1.77 (m, 1H, C(H)HCH.sub.3.sup.B), 1.77-1.60 (m, 1H, C(H)HCH.sub.3.sup.B) 1.01 (d, J.sub.H-H=6.7 Hz, CHCH.sub.3.sup.A) ppm.
N-(cyclohexylmethyl)aniline
[0330] ##STR00066##
[0331] N-methylaniline (54 mg, 0.5 mmol), cyclohexene (41 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 20 h. Yield 70%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.23-7.11 (m, 1H, m-C.sub.6H.sub.5), 6.68 (t, J.sub.H-H=7.2 Hz, 1H, p-C.sub.6H.sub.5), 6.60 (d, J.sub.H-H=8.9 Hz, 2H, 0-C.sub.6H.sub.5), 3.70 (br s, 1H, NH), 2.96 (d, J.sub.H-H=6.7 Hz, NCH.sub.2), 1.93-1.67 (m, 5H, CH.sub.2), 1.68-1.52 (m, 1H, CH), 1.39-1.21 (m, 3H, CH.sub.2), 1.11-0.93 (m, 1H, CH.sub.2) ppm. The chemical shifts for the title compound match those previously reported in the literature.
N-(cyclopentylmethyl)aniline
[0332] ##STR00067##
[0333] N-methylaniline (54 mg, 0.5 mmol), cyclopentene (34 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 20 h. Yield 74%. .sup.1H NMR (CDCl.sub.3, 300 MHz, 298 K): δ 7.21 (t, J.sub.H-H=7.5 Hz, 2H, m-C.sub.6H.sub.5), 6.72 (t, J.sub.H-H=7.3 Hz, 1H, p-C.sub.6H.sub.5), 6.65 (d, J.sub.H-H=7.7 Hz, 2H, o-C.sub.6H.sub.5), 3.69 (br s, 1H, NH), 3.06 (d, J.sub.H-H=7.3 Hz, 2H, NCH.sub.2), 2.19 (hept, J.sub.H-H=7.6 Hz, 1H, NCH.sub.2CH), 1.94-1.80 (m, 2H, CH.sub.2), 1.77-1.52 (m, 4H, CH.sub.2), 1.40-1.23 (m, 2H, CH.sub.2) ppm.
N-(cycloheptylmethyl)aniline
[0334] ##STR00068##
N-methylaniline (54 mg, 0.5 mmol), cycloheptene (49 mg, 0.5 mmol), Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 (13 mg, 0.025 mmol), L5 (8 mg, 0.025 mmol). Reaction time: 6 h. Yield 88%. .sup.1H NMR (400 MHz, CDCl.sub.3): δ 7.17 (t, J=7.4 Hz, 2H), 6.70 (t, J=7.2 Hz, 1H), 6.62 (d, J=8.0 Hz, 2H), 3.76 (br s, 1H), 2.97 (d, J=6.3 Hz, 2H), 1.90-1.40 (m, 11H), 1.35-1.20 (m, 2H).
Examples
[0335] Various alternative embodiments and examples are described herein. These embodiments and examples are illustrative and should not be construed as limiting the scope of the invention. In particular, while tantalum was used as the representative group 5 metal for these studies, the skilled person will expect other group 5 metals, and especially niobium, to perform similarly.
Example 1: Group 5 Metal-Based Precursors as Catalysts
[0336] In order to identify potentially promising group 5 metal/ligand salt combinations, the most common Ta precursors were screened in the absence of any ligand salt (Table 1). For this step, the standard benchmark reaction between N-methylaniline and 1-octene was chosen. It has previously been demonstrated that TaMe.sub.3Cl.sub.2 can catalyse this reaction, reaching a conversion of 91%, after 30 hours at 110° C. using a 10 mol % catalyst loading, but full conversion could never be achieved due to catalyst decay. Hence, optimization of the benchmark reaction was started by reducing the reaction time from 24 h to only 1 h. Under these conditions TaMe.sub.3Cl.sub.2 could afford a 28% conversion. Further catalytic screening confirmed that Ta-alkyl precursors can competently catalyse the addition of N-methylaniline to 1-octene, with Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 showing the most promising activity, achieving 39% conversion in only 1 h, when stoichiometric amounts of substrates were used. On the other hand, complexes bearing a Ta—NMe.sub.2 moiety were far less reactive, at best showing a 15% conversion after 24 hours of reaction. These data illustrated the promising catalytic activity of Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2. For this reason, Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 was chosen as the tantalum precursor for all subsequent catalytic experiments.
TABLE-US-00001 TABLE 1 Screening of Ta precursors for intermolecular hydroaminoalkylation reactions..sup.a
Example 2: Ligand Salt Screening Using In-Situ Experiments
[0337] Further catalytic experiments were performed by generating in situ the catalytic species by reacting Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 with a variety N,O-chelate type ligand salts.
[0338] This study was extended to internal alkenes, adding the more challenging cyclohexene to the pool of substrates. In an effort to perform the catalytic screening under milder conditions, the reaction temperature for reactions using cyclohexene as a substrate were lowered from 145° C. to 130° C. For this step, attention was focused on amidate (Table 2, L1), phosphoramidate (Table 2, L2), and pyridonate (Table 2, L3) sodium salts. In addition, a variety of ureate type ligand salts were also investigated. The latter type of ligands have previously been studied with group 4 metals for hydroamination and alkyne dimerization catalysis. Catalytic screening of in situ mixtures containing L1 and L2 resulted in no or poor conversion, regardless of the alkene substrate or the chosen reaction time. This behaviour is somewhat surprising considering that in the case of 1-octene, the related amidate-Ta(NMe.sub.2).sub.4 complex gave a 96% conversion of the addition product after 63 h of reaction time. Moreover, the in situ mixture between the ligand salt L2 and TaMe.sub.3Cl.sub.2 afforded 52% conversion after 20 h, at room temperature. On the other hand, using the less sterically encumbered pyridonate ligand salt L3 proved to be more successful as 31% and 33% conversions were observed for terminal and internal alkene substrates, respectively.
TABLE-US-00002 TABLE 2 Screening of ligand salts in hydroaminoalkylation reactions..sup.a
[0339] Next, ureate salts were tested. In situ catalyst system with L6 was excellent, affording 83% conversion in only 1 h for the reaction between 1-octene and N-methylaniline with a TOF of more than 16 h.sup.−1. However, when the more challenging cyclohexene substrate was evaluated, only a modest 19% conversion was observed after 20 h. Remarkably, the mixed aryl/alkyl-substituted ureate ligand L7 resulted in a reversed trend; this system provided higher conversion of the internal alkene substrate (20 h, 83%), but was less effective for the terminal alkene substrate (1 h, 12%). These results are surprising considering that the only change is the N-Ph group of L6 to the N-iPr moiety in L7. Exchanging the remaining Ph group of L7 with an iPr group (L8) did not improve the catalytic system and poor conversions were obtained for both alkenes. Without wishing to be bound by an particular theory, the inventors propose that that the known hemilability of N,O-chelating ligands coupled with the variable coordination modes of ureate ligands results in a flexible coordination environment about the reactive metal center, thereby promoting reactivity.
[0340] Table 3 provides additional data with respect to the effect of various ureate ligand salts on the addition of N-methylaniline to 1-octene.
TABLE-US-00003 TABLE 3 Screening of ligand salts in hydroaminoalkylation reactions in which N- methylaniline is added to 1-octene.
[0341] Table 4 provides additional data with respect to the effect of various ureate ligand salts on the addition of N-methylaniline to cyclohexene.
TABLE-US-00004 TABLE 4 Screening of ligand salts in hydroaminoalkylation reactions in which N- methylaniline is reacted with cyclohexene.
Example 3: Amine Substrate Scope
[0342] The study referred to in Tables 2 and 3 was extended by broadening the substrate scope in amine substrates. 1-Octene was kept as the preferred substrate for the terminal alkenes, whereas cyclohexene was swapped with cyclooctene, due to higher reactivity caused by the ring strain. As indicated in Table 5, catalytic mixtures including L6 were used to convert the terminal alkene, while ligand salt L7 was used exclusively for the internal alkene. Another objective was to purify the final products in an easy manner, by avoiding separation on the chromatographic column. For this reason, reaction times were adapted in order to favour full substrate conversion i.e. 2 h for 1-octene and 6 h for cyclooctene. As expected, the reaction between N-methylaniline and 1-octene (Table 5, Entry 1), resulted in a nearly complete conversion of the substrates with a TOF value of 9.5 h.sup.−1. Likewise, cyclooctene was fully converted within 6 hours, with an average of 3.3 turnovers per hour and an excellent 83% isolated yield (Table 5, Entry 1b). The pyridonate-Ta(NMe.sub.2).sub.3Cl.sub.2 complex can also catalyse this reaction, but in this case longer reaction times are needed (20 h), with a TOF value limited to 1 h.sup.−1. Error! Bookmark not defined.I Consistently with results reported in the literature, para-substituted N-methylanilines are well tolerated and good TOF values were recorded for both 1-octene (3-3.3 h.sup.−1) and cyclooctene (8.8-10 h.sup.−1) substrates. On the same note, the presence of halide substituents on the aromatic ring (Table 5, Entries 3-5) does not inhibit the reaction rates, opening the way for further functionalization via cross-coupling or nucleophilic aromatic substitution reactions. Perhaps more importantly, the potential pharmaceutically relevant aniline N-methyl-4-(trifluoromethoxy)aniline (Table 5, Entry 6) proved to be highly reactive under the specified catalytic conditions. Impressively, the presence of a dioxole unit was also well tolerated, as the corresponding addition product was easily obtained with an 85% yield.
TABLE-US-00005 TABLE 5 Substrate scope in amine.sup.a
[0343] Table 6 provides additional data with respect to the addition of various amines to 1-octene in the presence of tantalum metal complexes.
TABLE-US-00006 TABLE 6 Amine scope for hydroaminoalkylation reactions.
Example 4: Alkene Substrate Scope
[0344] Having tested the capability of the Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 containing catalytic system in broadening the substrate scope in amines, attention was switched to the alkene class of substituents (Table 7). In this respect, a variety of terminal, di-substituted alkenes and dienes were chosen as candidates. As before, L6 was used exclusively for terminal alkenes, while L7 was used in the case of the internal ones. Alkenes containing silyl protected OH moieties were easily reacted with N-methylaniline in less than 2 h to give the addition product in a 75% yield, and with an average of 8.6 turnovers per hour. Further catalytic screenings involved trimethyl(vinyl)silane, which upon reaction with N-methylaniline gives a 1:1 mixture (TOF=9.0 h.sup.−1) between the branched and linear product, perhaps as a consequence of the β-silicon effect. Even sterically hindered alkenes such as vinylcyclohexene and methylenecyclohexane are accommodated giving the corresponding addition products in excellent yields and TOF values of 9.1 h.sup.−1 and 6.6 h.sup.−1, respectively. Remarkably, 4-vinylcyclohex-1-ene was highly reactive under catalytic conditions (99% yield, TOF=10 h.sup.−1), when only the terminal C═C bond was selectively activated. This result is impressive as isolated dienes are particularly difficult to convert. Styrenes are no exception to the active class of substituents as 4-chlorostyrene and 2-bromo-styrene reacted quantitatively (TOF=10 and 10 h.sup.−1) with the amine, with no signs of polymerized product being observed. In the case of 2-bromo-styrene, the presence of the halide atom in the ortho position on the aryl ring notably does not sterically affect the outcome of the reaction. This observation is counterintuitive considering that under identical conditions, 2-methylstyrene was found to be completely inert.
[0345] The substrate scope containing the more challenging internal alkenes was investigated next. First, α-methylstyrene required long reaction times (48 h) to ensure an almost complete conversion. α-methylstyrene can be fully converted in 24 h when the catalyst is supported by the smaller pyridonate type of ligands. The reactivity of cyclic internal alkenes was found to be directly proportional to the size of the ring, and therefore dependant on the ring strain. Hence, cyclooctene was found to be the most reactive (TOF=3.2 h.sup.−1), followed by cycloheptene (TOF=3 h.sup.−1), while cyclopentene (TOF=0.79 h.sup.−1) and cyclohexene (TOF=0.80 h.sup.−1) displayed a similar reactivity. Absence of the ring strain, as observed for the internal linear alkenes had a clear impact on the reactivity of these substrates. Indeed, compared to the cyclic alkenes, only moderate yields were obtained after 20 h i.e. 4-octene (55%), cis-3-hexene (55%), trans-3-hexene (32%).
TABLE-US-00007 TABLE 7 Substrate scope in alkene..sup.a,b Turnover frequency values (h) are given in brackets. Ratio of branched:linear regioisomers are given in square brackets
[0346] Table 8 provides additional data with respect to the addition of N-methyl butylamine to various alkenes.
TABLE-US-00008 TABLE 8 Addition of various alkenes to N-methyl butylamine.
[0347] Table 9 provides additional data with respect to the effect of various ureate ligand salts and metal complexes on the addition of piperidine to styrene.
TABLE-US-00009 TABLE 9 Screening of ligand salts in hydroaminoalkylation reactions in which piperidine is reacted with styrene.
Example 5: Hydroamination Reaction Between Piperidine and 1-Octene
[0348] Tables 10 and 11 provides data with respect to the effect of various ureate ligand salts and metal complexes on the addition of piperidine to 1-octene.
TABLE-US-00010 TABLE 10 Hydroaminoalkylation data using cyclic ureate salts and Ta(CH.sub.2SiMe.sub.3).sub.3Cl.sub.2 for the reaction between piperidine and 1-octene.
TABLE-US-00011 TABLE 11 Ligand Temperature (°C.) Time (h) Conversion (%)
Example 6. Effect of Temperature on Hydroaminoalkylation
[0349]
Example 8. Effect of Catalyst Concentration on Hydroaminoalkylation
[0350]
Example 7. Effect of Halide Salts on Hydroaminoalkylation
[0351]
[0352] The experiments which were performed in the presence of an internal standard (1,3,5-trimethoxybenzene) show that all employed vinyl terminated polyolefins can be successfully aminated with aromatic and alkylamines in as little as 2 hours. Recorded data shows that when N-methylaniline and N-methylcyclohexylamine are used as amine substrates, the temperature can be as low as 110° C. On the other hand, reactions employing N-methylbutylamine require 145° C. to reach full conversion.
Example 8. Amination of Polyolefins
[0353]
[0354] Table 12 summarizes the results of amination of representative polyolefins, i.e vinyl-terminated polypropylene and a vinyl-terminated ethylene polypropylene copolymer, with three representative amines (N-methylaniline, N-methylcyclohexylamine, or N-methylbutylamine) using .sup.tBuLTa(CH.sub.2SiMe.sub.3).sub.3Cl as a representative catalyst.
TABLE-US-00012 TABLE 12 Postpolymerization modification of polyolefins .sup.a
[0355]
[0356]
[0357]
[0358]
[0359]
[0360]
[0361]
[0362]
[0363]
[0364] The experiments which were performed in the presence of an internal standard (1,3,5-trimethoxybenzene) show that each of the employed polyolefins can be successfully aminated with aromatic and alkylamines in as little as 2 hours. When N-methylaniline and N-methylcyclohexylamine are used as amine substrates, the temperature can be as low as 110° C. Based on NMR experiments the initial both the initial polymers and the resulting ones have a molecular weight range between 350-3500 g/mol.
Operation
[0365] While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.