Kinetic studies on the hydrosilylation of phenylacetylene with R3SiH (R3?=?PhMe2, Ph2Me, Ph3, Et3) using bis(1,2-diphenylphosphinoethane)norbornadiene rhodium(I) hexafluorophosphate as catalyst

Cervantes, Jorge; González‐Alatorre, Guillermo; Rohack, Diane; Pannell, Keith H.

doi:10.1002/(sici)1099-0739(200003)14:3<146::aid-aoc965>3.0.co;2-x

Cited by 9 publications

(6 citation statements)

References 33 publications

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“…In these cases, considerable amounts of the α and β-( Z ) vinylsilanes were also formed except for 17 , which gave only the β-( E ) and α isomers. The lack of selectivity in hydrosilylation of phenylacetylene has also been observed with cationic rhodium(I) precursors containing diphosphine as ancillary ligands …”

Section: Resultsmentioning

confidence: 85%

“…The lack of selectivity in hydrosilylation of phenylacetylene has also been observed with cationic rhodium(I) precursors containing diphosphine as ancillary ligands. 40 The hydrosilylation of tert-butylacetylene at room temperature is quite slow and even at 60 o C long reaction times are generally required. Under these experimental conditions the reactions are unselective since although the β-(E) vinylsilane is the major product (50-75%), variable amounts of the β-(Z) (5-12%) and α (8-35%) isomers were also formed.…”

Section: Synthesis Of Neutral and Cationic Rhodium(i) Complexes Contamentioning

confidence: 99%

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Rhodium(I) Complexes with Hemilabile N-Heterocyclic Carbenes: Efficient Alkyne Hydrosilylation Catalysts

et al. 2007

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A series of alkylammonium-imidazolium chloride salts [RImH(CH 2) n NMe 2 ]Cl•HCl (R = Me, t-Bu, Mes, n = 2, 3) have been prepared by alkylation of 1-substituted imidazole compounds with the corresponding chloro-alkyl-dimethylamine hydrochloride. These salts are precursors for the synthesis of a library of rhodium (I) complexes containing amino-alkyl functionalized N-heterocyclic carbene (NHC) ligands with hemilabile character by varying the substituent on the heterocyclic ring and the length of the linker with the dimethylamino moiety. The monodeprotonation of alkylammoniumimidazolium salts with NaH in the presence of [{Rh(µ-Cl)(cod)} 2 ] gave the amino-imidazolium salts [RImH(CH 2) n NMe 2 ][RhCl 2 (cod)]. Further deprotonation with NaH under non anhydrous conditions gave the neutral complexes [RhCl(cod)(RIm(CH 2) n NMe 2)] in good yields. The abstraction of the chloro ligand by silver salts rendered the cationic complexes [Rh(cod)(κ 2 C,N-RIm(CH 2) 3 NMe 2)][BF 4 ] (R = Me, Mes) by coordination of the NMe 2 fragment of the sidearm of the functionalized NHC ligands. The catalytic activity of the rhodium complexes in the hydrosilylation of terminal alkynes using HSiMe 2 Ph has been investigated with Ph-C≡CH, t-Bu-C≡CH, n-Bu-C≡CH, and Et 3 Si-C≡CH as substrates. Higher activities were achieved using neutral complexes having small substituents at the heterocyclic ring (R = Me). Excellent selectivities in the β-(Z)-vinylsilane isomer were found in the hydrosilylation of 1hexyne and predominantly the β-(E) and α-bis(silyl)alkene isomers were obtained in the hydrosilylation of triethylsilylacetylene.

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Section: Resultsmentioning

confidence: 85%

Section: Synthesis Of Neutral and Cationic Rhodium(i) Complexes Contamentioning

confidence: 99%

Rhodium(I) Complexes with Hemilabile N-Heterocyclic Carbenes: Efficient Alkyne Hydrosilylation Catalysts

et al. 2007

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“…The product ratios obtained in the triphenylsilane and triethoxysilane hydrosilylations of phenylacetylene are most significant, since other transition-metal catalysts which give high selectivity for this hydrosilylation most often involve triethylsilane. ,,,,, Commonly used platinum catalysts, H 2 PtCl 6 ·6H 2 O and [Bu 4 N] 2 [PtCl 6 ], give 3 -β- E stereoselectively, but, at best, the 3 -β- E to 3 -α ratio is 95:5 after reaction at 140 °C for 3 h . The most commonly used rhodium catalyst, RhCl(PPh 3 ) 3 , gives a mixture of the isomers, although 3 -β- E is preferred.…”

mentioning

confidence: 99%

“…The most commonly used rhodium catalyst, RhCl(PPh 3 ) 3 , gives a mixture of the isomers, although 3 -β- E is preferred. Another rhodium catalyst, [(nbd)(dppe)Rh]PF 6 (nbd = norbornadiene, dppe = 1,2-bis(diphenylphosphino)ethane), gives no 3 -β- Z but there is some α isomer formed. The best catalyst to date, [cymeneRuCl 2 ] 2 , exhibited high selectivity for 3 -β- Z (β- Z :β- E :α = 96:4:0) .…”

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confidence: 99%

Tunable Stereoselective Hydrosilylation of PhC⋮CH Catalyzed by Cp*Rh Complexes

Faller

D'Alliessi

2002

Organometallics

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The catalysts [Cp*RhCl2]2 and [Cp*Rh(BINAP)](SbF6)2 (Cp* = pentamethylcyclopentadienyl; BINAP = 2,2‘-bis(diphenylphosphino)-1,1‘-binaphthyl) are effective for the hydrosilylation of phenylacetylene with triethylsilane, triethoxysilane, and triphenylsilane under mild conditions. [Cp*RhCl2]2 promotes the atypical anti addition to yield the β-Z isomer, whereas [Cp*Rh(BINAP)](SbF6)2 gives syn addition to form the β-E isomer. Extraordinarily high regioselectivity and stereoselectivity were observed for reactions involving triphenylsilane. Thus, tuning of the ligand set of Cp*Rh allows preparation of either the β-Z or β-E product.

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“…Under these reaction conditions, both catalysts showed good activity in the hydrosilylation of 1‐hexyne, with a clear preference for the formation of the anti‐Markovnikov anti‐addition β‐( Z )‐vinylsilane product, which reaches 69 % yield if the dimetallic catalyst 2 was used (Table , entry 2). This observation is very interesting, because the β‐( Z ) product is the less frequent product in this reaction, and thus a very elusive target ,. Catalyst 2 is more active than catalyst 1 in the hydrosilylation of phenylacetylene with HSiMe 2 Ph, and also more selective in the production of the β‐( Z )‐vinylsilane (56 % yield, entry 4).…”

Section: Resultsmentioning

confidence: 98%

Immobilization of Pyrene‐Adorned N‐Heterocyclic Carbene Complexes of Rhodium(I) on Reduced Graphene Oxide and Study of their Catalytic Activity

Ruiz-Botella

Peris

2017

ChemCatChem

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Two pyrene‐tagged N‐heterocyclic carbene (NHC) complexes of rhodium(I) were obtained and characterized. The two complexes were supported onto reduced graphene oxide (rGO), generating two new materials in which the molecular complexes are immobilized by π–π stacking interactions onto the surface of the solid. The catalytic activity of both complexes and solid hybrid materials were studied in the 1,4‐addition of phenylboronic acid to cyclohex‐2‐one, and in the hydrosilylation of terminal alkynes. The studies showed that for both reactions, the dimetallic complex displayed better catalytic performances than the monometallic one. This accounted for both the reactions performed in homogeneous conditions and for the reactions performed with the solid. In the case of the addition of phenylboronic acid to cyclohexanone, the solid containing the dimetallic catalyst could be effectively recycled up to five times, with negligible loss of activity, whereas the monometallic catalyst rapidly became inactive. In the hydrosilylation of terminal alkynes, the selectivity towards the β‐(Z)vinylsilane was improved if the immobilized dimetallic catalyst was used, although the catalyst started to lose activity after the second run.

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Kinetic studies on the hydrosilylation of phenylacetylene with R3SiH (R3?=?PhMe2, Ph2Me, Ph3, Et3) using bis(1,2-diphenylphosphinoethane)norbornadiene rhodium(I) hexafluorophosphate as catalyst

Cited by 9 publications

References 33 publications

Rhodium(I) Complexes with Hemilabile N-Heterocyclic Carbenes: Efficient Alkyne Hydrosilylation Catalysts

Rhodium(I) Complexes with Hemilabile N-Heterocyclic Carbenes: Efficient Alkyne Hydrosilylation Catalysts

Tunable Stereoselective Hydrosilylation of PhC⋮CH Catalyzed by Cp*Rh Complexes

Immobilization of Pyrene‐Adorned N‐Heterocyclic Carbene Complexes of Rhodium(I) on Reduced Graphene Oxide and Study of their Catalytic Activity

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