Asymmetric Synthesis of Chiral 1,3-Disubstituted Allylsilanes via Copper(I)-Catalyzed 1,4-Conjugate Silylation of α,β-Unsaturated Sulfones and Subsequent Julia-Kocienski Olefination

Main observation and conclusion A general synthesis of chiral 1,3-disubstituted allylsilanes is established through copper(I)-catalyzed asymmetric 1,4-conjugate silylation of alpha,beta-unsaturated sulfones and subsequent Julia-Kocienski olefination. By modification of McQuade's NHC ligand, the catalytic asymmetric conjugate silylation with a broad substrate scope is achieved in high enantioselectivity. The following Julia-Kocienski olefination proceeds smoothly at room temperature to deliver an array of chiral allylsilanes in moderate yields. More interestingly, a one-pot asymmetric synthesis with high synthetic efficiency is successfully realized. Utility of the prepared chiral 1,3-disubsituted allylsilanes is demonstrated in the asymmetric allylation of both aldehyde and aldimine. Finally, an interesting "match and mismatch" phenomenon is observed in the asymmetric allylation of chiral aldehydes.