Synthesis of α,α-disubstituted α-acetoxy esters and α,α-disubstituted α-hydroxy acids by Baeyer-Villiger oxidation of the corresponding β-ketoesters

The regioselective Baeyer-Villiger oxidation of a wide range of alpha,alpha-disubstituted beta-ketoesters has been developed to synthesize, in good yields, alpha,alpha-disubstituted alpha-acetoxy esters. The reactions were performed using m-chloroperbenzoic acid in the presence of triflic acid. The rearrangement was shown to occur with retention of configuration of the migrating group. The corresponding alpha,alpha-disubstituted alpha-hydroxy acids were obtained in good yields, after hydrolysis.