Selective O-acylation of silyl enol ethers with acid halides mediated by a copper(I) salt

A new selective synthetic method of enol esters (O-acylated products) from silyl enol ether and acid chloride in the presence of CuCl is described. This reaction proceeds smoothly in DMI (1,3-dimethyl-2-imidazolidinone) but not in a less polar solvent. The silicon-copper exchange reaction pathway is proposed for this transformation as in the cases of hydrosilane and alkynylsilane which were previously reported.