electron-withdrawing group on the α-carbon using tris(triphenylphosphine)chlororhodium as a catalyst is described. Solvolysis of these silyl ethers and silyl enol ethers afforded the corresponding reduced products. The hydrosilylation of α,β-unsaturated carbonyl compounds was found to proceed by 1,4-addition. An oxidative adduct of triethylsilane to the rhodium-(I) complex was obtained as a reaction intermediate
The use of dirhodium(II) catalysts in the 1,4-hydrosilylation of alpha,beta-unsaturated ketones and aldehydes was explored. Dirhodium(II) tetrakis(perfluorobutyrate), Rh2(pfb)4, proved to be the catalyst of choice for this process, providing the corresponding silyl enol ethers in high yields.
Extended Stereocontrol in Silyl Group-Transfer Cyclizations: Control of Four Contiguous Chiral Centers
作者:Peter G. Klimko、Daniel A. Singleton
DOI:10.1055/s-1994-25618
日期:——
The potential for extended stereocontrol in silyl group-transfer cyclizations was explored in model studies which formed four contiguous chiral centers. The diastereofacial selectivity for the reaction of cyclized intermediates was outstanding for both fluoride and SnCl2 trityl chloride mediated reactions. Good simple diastereoselectivity was observed in reactions initiated by prochiral silyl enolates.