α-Silicon effect assisted Curtin-Hammett allylation using allylcopper reagents derived from 1,3-dienylsilanes

Chem Sci. 2019 Jun 28;10(32):7554-7560. doi: 10.1039/c9sc02905b. eCollection 2019 Aug 28.

Abstract

Cu-catalyzed stereoselective synthesis of (E)-δ-silyl-anti-homoallylic alcohols from 1,3-dienylsilane was developed. Mechanistic studies revealed that the borocupration of dienylsilane proceeded through a 1,2-addition pathway to give an allylcopper intermediate with Cu distal to the silyl group. However, the subsequent aldehyde allylation proceeded via Curtin-Hammett control to give (E)-δ-silyl-anti-homoallylic alcohols with high diastereoselectivities. This method was applied to the synthesis of the C1-9 fragment of a polyketide natural product, mycinolide IV.