The Baeyer–Villiger reaction

This chapter deals with various facets of the Baeyer–Villiger reaction, a classical oxidation process that converts ketones to esters, and remains of wide synthetic applicability. The reaction occurs via the Criegee tetrahedral intermediate formed from the ketone and peracid reactants. After a brief overview of the mechanistic background—with particular emphasis on stereoelectronic effects—the synthetic applications of the reaction are covered in detail (based on type of ketone). Regioselectivity and stereoselectivity are crucially determined by the migratory aptitudes of groups in the ketone, during the collapse of the Criegee intermediate. This aspect is discussed in considerable depth and detail, including the (occasional) breakdown of the migratory aptitude order. The wide range of oxidants, catalysts, and conditions (including ionic liquids) are discussed, followed by the application of the Baeyer–Villiger reaction as a strategy in asymmetric synthesis (both kinetic resolutions and desymmetrizations). The final sections deal with the rapidly evolving area of enzyme-catalyzed Baeyer–Villiger reactions, including mutation-induced design of monooxygenases; and focused discussions of naturally occurring Baeyer–Villiger reactions and certain commercial applications.