Gallium Trihalide Catalyzed Sequential Addition of Two Different Carbon Nucleophiles to Esters by Using Silyl Cyanide and Ketene Silyl Acetals

A sequential addition of silyl cyanide and ketene silyl acetals to esters was achieved by a gallium trihalide catalyst to produce β‐cyano‐β‐siloxy esters. This is the first example of the sequential addition of two different carbon nucleophiles to esters. The employment of lactones provided α,α‐disubstituted cyclic ethers with a cyano group and an ester moiety. A variety of esters and lactones are applicable to this reaction system. New on the block: The reaction of esters with silyl cyanide and ketene silyl acetals in the presence of a gallium trihalide catalyst was established to produce a new synthetic route to β‐cyano‐β‐siloxy esters (see scheme). This is the first report for the sequential addition of two different carbon nucleophiles to esters via a facile and practical procedure. Lactones were also transformed to α,α‐disubstituted cyclic ethers with a cyano group and an ester moiety.