Ethyl alpha-fluoro silyl enol ether: stereoselective synthesis and its aldol reaction with aldehydes and ketones.

Ethyl alpha-fluoro silyl enol ether is stereoselectively synthesized in high yield from inexpensive chlorofluoroacetate and Mg (or Zn) in DMF (or HMPA). Lewis acid promoted aldol reaction of this enol ether with aldehydes and ketones gives alpha-fluoro-beta-hydroxy esters in good to excellent yields.