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 α,ααdisubstituted β-ketoesters has been developed to synthesize, in good yields, α,α-disubstituted α-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 α,ααdisubstituted α-hydroxy acids were obtained in good yields, after hydrolysis.