Asymmetric Synthesis of Chiral 1,<scp>3‐Disubstituted</scp> Allylsilanes <i>via</i> Copper(I)‐Catalyzed 1,<scp>4‐Conjugate</scp> Silylation of α,<scp>β‐Unsaturated</scp> Sulfones and Subsequent <scp>Julia‐Kocienski</scp> Olefination
Xianliang Wang, Xing‐Hao Yin, Jun‐Zhao Xiao, Xueshun Jia, Liang Yin
Abstract
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 α,β‐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.