A Michael addition and alkylation sequence using m methyl 2-(trimethylsily)-propenoate. Stereoselective synthesis of α-silyl esters

Michael addition of organomagnesiums or -lithiums with methyl 2-(trimethylsilyl)propenoate leads to either 1:1 or 1:2 adduct anions, depending upon the reaction condition and the reactivity of donor molecules. The adduct anions, both 1:1 and 1:2 types, are quenched with alkyl halides or water in a highly stereoselective manner to produce α-silylated esters. A rigid intramolecular chelation working in the adduct anions is partly responsible for the high selectivity.