- A modular assembly of chiral oxazolinylcarbene-rhodium complexes: Efficient phosphane-free catalysts for the asymmetric hydrosilylation of dialkyl ketones
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A novel class of chiral bidentate ligands with a carbene and an oxazoline moiety is obtained by the coupling of N-arylimidazoles and a 2-bromooxazoline derivative. The rhodium complex 1 catalyzes the hydrosilylation of aryl alkyl ketones and otherwise problematic dialkyl ketones in high yields and good enantioselectivities (up to 95% ee).
- Gade, Lutz H.,Cesar, Vincent,Bellemin-Laponnaz, Stephane
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- Asymmetric Catalyses, 14. Enantioselective Hydrosilylation of Prochiral Ketones with Rh- and Pt-Complexes of Optically Active N-Chelate Ligands
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N-chelate ligands with a lateral chiral center, which derive from optically active primary amines, amino acids, and amino acid derivatives, catalyze in Rh and Pt complexes the enantioselective hydrosilylation of acetophenone, benzyl methyl ketone, and tert-butyl methyl ketone with diphenyl- and 1-naphthylphenylsilane.The ketones are transformed into the corresponding silyl ethers which on hydrolysis yield the alcohols 1-phenylethanol, 1-phenyl-2-propanol and 3,3-dimethyl-2-butanol. 37 N ligands 1 - 37 with 2 (I) and K (XX) as well as 21 isolated complexes II - XIX and XXI - XXIII are tested.The best optical inductions exceed considerably those which were obtained with optically active phosphane containing catalysts used up to now.
- Brunner, Henri,Reiter, Barbara,Riepl, Georg
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p. 1330 - 1354
(2007/10/02)
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