Novel sequential 1,2-Brook/Wittig reactions were developed for the preparation of silyl enol ethers.This method enables highly selective preparation of both geometric isomers of glyoxylate silyl enol ethers,u sing aldehydes (E-selective) and tosylimines (Z-selective) as aWittig electrophile.The saltfree conditions of this reaction system are likely to be advantageous for switching the selectivity.T he optimal reaction conditions and generality of the reaction were investigated, and plausible explanations for the observed selectivity were also discussed.