Synthesis of α,β‐Unsaturated Ketones by Pd‐Catalyzed Decarboxylative Allylation of α‐Oxocarboxylates

A palladium/p-tolylphosphine system has been developed that catalyzes the extrusion of carbon dioxide from α-oxocarboxylic acid allyl esters, leading to α,β-unsaturated ketones (see scheme). The palladium complex activates the substrate and mediates the carbon–carbon bond formation to give allyl ketones, and subsequent double bond shift to the α,β position. The actual decarboxylation step with formation of the acyl nucleophile is promoted by phosphine.