Efficient Enantioselective Hydrosilylation of Aryl Ketones Catalyzed by a Chiral BINAP‐Copper(<scp>I</scp>) Catalyst‐Phenyl(methyl)silane System

Issenhuth, Jean Thomas; Dagorne, Samuel; Bellemin‐Laponnaz, Stéphane

doi:10.1002/adsc.200606152

Cited by 65 publications

(14 citation statements)

References 8 publications

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“…Upon changing the solvent from pure toluene (83% ee) to a toluene:THF mixture an im- asc.wiley-vch.de proved selectivity was observed reaching its optimum for a solvent ratio of 8:3 (94% ee). However, in contrast to the results obtained under similar reaction conditions by Bellemin-Laponnaz et al, [20] the selectivity remained unchanged upon variation of the silane from diphenylsilane (ee = 94%) to phenylsilane (ee = 94%) or phenylmethylsilane (ee = 93%). Testing the unfunctionalised BINAP as ligand under these optimised reaction conditions gave a selectivity of 91% ee indicating a slight improvement in the enantioselectivity of the hydrosilylation of acetophenone (3% ee) due to the functionalisation of the BINAP in the 6-position with an aminomethyl group.…”

Section: The Enantioselective Cu-catalysed Hydrosilylation Of Acetophcontrasting

confidence: 77%

“…Using acetophenone as substrate the BINAP ligand was found to give a relatively low enantioselectivity of 75% compared to other diphosphine ligands tested by Lipshutz et al [19] By variation of the reaction conditions the selectivity could be improved to over 90%. [20] We report the results of dendrimer immobilisation for this reaction in this work.…”

Section: Introductionmentioning

confidence: 96%

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Synthesis of Peripherally Functionalised Dendritic Binaphthyl (BINAP)‐Systems and their Application as Ligands in the Copper‐Catalysed Hydrosilylation of Acetophenone

Kassube¹,

Wadepohl²,

Gade³

2008

Adv Synth Catal

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Two series of peripherally functionalised dendrimers were synthesised based on poly(ethyleneimine) and poly(amidoamine) (PAMAM) dendri-A C H T U N G T R E N N U N G mers by reaction of (R)-6-N- [(g-carboxyl)butanoyl]-aminomethyl-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ("Glutaroyl-Aminap") with first to fifth generation PPI and zeroth to fourth generation PAMAM dendrimers using ethyl-N,N-dimethylcarbodiimide (EDC)/1-hydroxybenzotriazole as coupling reagents. All dendritic ligands were characterised by NMR spectroscopy, elemental analysis and, for generations G0-G3, MALDI-TOF mass spectrometry. The relationship between the size/generation of the dendritic ligands and their catalytic properties was established in the asymmetric hydrosilylation of acetophenone. It could be shown that (R)-6-aminomethyl-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ("HAminap") can be attached to the dendrimers without any significant loss of catalytic selectivity compared to the monomeric ligand Benzoyl-Aminap. The selectivities observed in these reactions were higher than those obtained using unfunctionalised BINAP as ligand.

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Section: The Enantioselective Cu-catalysed Hydrosilylation Of Acetophcontrasting

confidence: 77%

Section: Introductionmentioning

confidence: 96%

Synthesis of Peripherally Functionalised Dendritic Binaphthyl (BINAP)‐Systems and their Application as Ligands in the Copper‐Catalysed Hydrosilylation of Acetophenone

Kassube¹,

Wadepohl²,

Gade³

2008

Adv Synth Catal

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“…[15] More recently, we reported that the commercially available chiral phosphane BI-NAP may be a suitable supporting ligand for highly enantioselective copper-catalyzed asymmetric hydrosilylation reactions of ketone substrates. [16] Scheme 1. Asymmetric hydrosilylation of aryl alkyl ketones with copper(I) as catalyst.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Studies on the Copper‐Catalyzed Hydrosilylation of Ketones

et al. 2010

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The copper‐catalyzed asymmetric hydrosilylation of ketones is an efficient method for the synthesis of chiral enantiopure secondary alcohols. Herein, we present a detailed computational study (DFT/B3LYP) of the copper(I)‐catalyzed reaction. In particular, the two transition states involved in the catalytic cycle have been determined. The insertion of the ketone into the Cu–H bond was found to have a lower activation barrier than the reaction of the copper alkoxy intermediate with the silane, which regenerates Cu–H along with the silyl ether product. Our findings also reveal the importance of the copper hydride dimer in controlling the reactivity toward the ketone. The conclusions are supported by experimental mechanistic investigations including kinetic studies, kinetic isotope effect, and isotope labeling measurements.

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“…Using acetophenone as substrate the BINAP-Cu catalyst was found to give moderate enantioselectivity (75% ee) compared with other diphosphine ligands tested by Lipshutz et al [8] By variation of the reaction conditions the enantioselectivity could be improved to over 90% ee. [9] Fan et al synthesised a variety of functionalised BINAP-ligands bearing dendritic wedges. [10][11][12][13][14][15] To attach the polyaryl ether dendrons to the ligand they introduced amino groups in the 5-or 5,5'-positions.…”

Section: Introductionmentioning

confidence: 99%

Immobilisation of the BINAP Ligand on Dendrimers and Hyperbranched Polymers: Dependence of the Catalytic Properties on the Linker Unit

2009

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A series of immobilised Carbo-BINAP ligands has been synthesised using poly(propylene imine) (PPI) dendrimers as soluble supports. They contain up to 64 BINAP ligands at their periphery without an additional linking unit. Despite the high steric requirements of the ligand, all dendrimers could be completely functionalised, resulting in the immobilised systems in good yields. Furthermore, the immobilisation strategy that worked out for the fixation of AMINAP ligands with additional linking units as well as of Carbo-BINAP ligands without additional linking units on dendrimers has thus been extended to less regularly hyperbranched poly(ethylene imines) (PEI) as soluble supports. In that way it has been possible to attach on average 9, 26, and 138 Glutaroyl-AMINAP or Carbo-BINAP ligands to PEIs of different molecular weights. The catalytic properties of these systems in the copper-catalysed hydrosilylation of acetophenone were investigated. The dendritic PPI-bound Carbo-BINAP ligands displayed a strong dependence of enantioselectivity and activity on the generation of the dendrimer. For the Carbo-BINAP and Glutaroyl-AMINAP ligands immobilised on the hyperbranched polymers, however, activities and enantioselectivities comparable to those of the mononuclear catalysts were found. The macromolecular, immobilised BINAP ligands could be recycled several times without any observable loss of activity or enantioselectivity.

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Efficient Enantioselective Hydrosilylation of Aryl Ketones Catalyzed by a Chiral BINAP‐Copper(I) Catalyst‐Phenyl(methyl)silane System

Abstract: Abstract:The Cu(I)-chiral diphosphine (BINAP) system was found to efficiently catalyze the hydrosilylation of aryl alkyl ketones with excellent enantioselectivities by using phenylA C H T U N G T R E N N U N G (methyl)silane as stoichiometric hydride source.

Cited by 65 publications

References 8 publications

Synthesis of Peripherally Functionalised Dendritic Binaphthyl (BINAP)‐Systems and their Application as Ligands in the Copper‐Catalysed Hydrosilylation of Acetophenone

Synthesis of Peripherally Functionalised Dendritic Binaphthyl (BINAP)‐Systems and their Application as Ligands in the Copper‐Catalysed Hydrosilylation of Acetophenone

Mechanistic Studies on the Copper‐Catalyzed Hydrosilylation of Ketones

Immobilisation of the BINAP Ligand on Dendrimers and Hyperbranched Polymers: Dependence of the Catalytic Properties on the Linker Unit

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