The mechanism of the protodesilylation of allylsilanes which are disubstituted on C-3

Abstract

3,3-Dialkylallylsilanes react with protons by two delicately balanced mechanisms. The allylsilane (5) reacts directly by protonation on C-3 of the allyl group, followed by loss of the silyl group. On the other hand, the allylsilanes (7) and (10) react, at least in part, by protonation on C-2, followed by hydride shift and loss of the silyl group. The overall result is the same, but the different pathways were revealed by using a deuteron in place of the proton.