Palladium-catalyzed divergent reactions of α-diazocarbonyl compounds with allylic esters: Construction of quaternary carbon centers

Take two: α-Diazocarbonyl compounds display a diverse pattern of reactivity upon palladium-catalyzed reaction with esters. Esters bearing an alkynyl group on the carbonyl carbon atom lead to two different C-C bonds at the same carbon atom in a single operation through decarboxylation and migratory insertion, whereas aromatic and benzylic acid derivatives afford aromatic and benzylic esters bearing an O-substituted quaternary carbon center.