A new practical synthesis of silyl enol ethers

Abstract A new, practical route to enoxysilanes is described from simple enolizable aldehydes or ketones, using the trimethylchlorosilane-sodium iodide—tertiary amine reagent in acetonitrile. From certain aldehydes, an onium intermediate has been isolated. A conformational study of this onium intermediate and a thermal unimolecular syn-elimination process may explain the stereoselectivity of the reaction. Such an interpretation can be extended to all the aldehydes and ketones considered, Steric factors related to the nature both of the carbonyl derivative and of the amine play a capital role for the regio- as well as for the stereo-control of the reaction