Enantioselective Baeyer-Villiger Oxidations

The Baeyer-Villiger oxidation of ketones represents a powerful methodology in synthesis to break carbon-carbon bonds in an oxygen insertion process. Since the discovery of the reaction by Adolf Baeyer and Victor Villiger in 1899 substantial progress has been made to understand the mechanism, to predict migratory preference, and to apply this conversion in preparative chemistry. Chiral Baeyer-Villiger oxidation of cyclic ketones allows rapid access to asymmetric lactones as valuable intermediates in organic chemistry and frequently encountered precursors in enantioselective synthesis. In recent years, organometal catalysts and other artificial catalytic entities have been continuously improved and represent promising approaches for future process developments. Complementing this strategy, biocatalysis offers a “green chemistry” alternative for this transformation. This review will give a comprehensive summary of strategies to perform Baeyer-Villiger reactions in an enantioselective manner. A discussion of scope and limitations of both organometallic approaches and biocatalytic methods includes substrate profiles, improvement of optical purity, and implications upon scale-up.