Enantioselective Acylation of Silyl Ketene Acetals through Fluoride Anion-Binding Catalysis

A highly-enantioselective acylation of silyl ketene acetals with acyl fluorides has been developed to generate useful \(\alpha\), \(\alpha\)-disubstituted butyrolactone products. This reaction is promoted by a new thiourea catalyst and 4-pyrrolidinopyridine and represents the first example of enantioselective thiourea anion-binding catalysis with fluoride.