Asymmetric Malonic and Acetoacetic Acid Syntheses – A Century of Enantioselective Decarboxylative Protonations

The enantioselective decarboxylative protonation (EDP) of malonic or acetoacetic acid derivatives is a synthetic methodology by which the chirality of the product is generated during the enol/enolate protonation step. Although EDP is a century‐old reaction, it has not received much attention until recently. This review focuses on the EDP as an alternative to the strong‐base‐mediated deprotonation/asymmetric reprotonation for the stereocontrol of C–H bond formation. The diverse synthetic approaches are classified according to the type of catalysis used, which are organic, metallic or enzymatic.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)