Silylene oxonium ylides: di-tert-butylsilylene insertion into C–O bonds

Allylic ethers undergo insertions of silylenes into C–O bonds to form allylic silanes. Silylene insertion into C–O acetal bonds was also observed. Formation of silylene ylide intermediates led to [1,2]-Stevens rearrangement products as well as [2,3]-sigmatropic products depending upon the steric environment of the starting allylic ether.