Stereoselective Formation of Cyclopropylsilane through Intramolecular Rearrangement of [(Allyloxy)dimesitylsilyl]lithiums (SYNTHETIC ORGANIC CHEMISTRY-Synthetic Design)

Abstract

A [(sec-allyloxy)dimesitylsilyl]stannane having a phenyl group on the olefin part reacts with n-BuLi in THF to give a cyclopropylsilane as a single diastereomer, in contrast to the [2, 3]-sila-Wittig rearrangement affording an allylsilane, previously observed for a substrate having an alkyl group on the olefin part. The substituent effect is revealed by ab initio calculations in terms of the regioselectivity in the reaction of silyllithiums with an olefin.