Controlling Selectivities in Palladium-Catalyzed Cyclization Reactions Leading to Heterocycles: From Ambiphilic Reactions of Arylpalladium Species to Carbene Insertions

Abstract Selectivity control of palladium-catalyzed reactions constitutes a highly attractive tool in organic synthesis that has been widely applied. However, while the ambiphilic character of σ-organopalladium species has been repeatedly revealed, little effort has been dedicated to the selective promotion of either their electrophilic or nucleophilic reactivity from the same starting material. This chapter provides an overview of our work on the control of the potential ambiphilic nature of σ-organopalladium intermediates in intramolecular reactions with carbonyl derivatives. It also summarizes how palladium can be used to control the selectivity of intramolecular metal-carbenoid C–H insertion reactions of α-diazo carbonyl derivatives. In both cases, a combination of experimental and computational studies has been used to rationalize the different reaction pathways involved in the transformations. The diverse reactivities of organopalladium compounds described herein open new avenues in organic synthesis, and they are expected to have a broad application in the construction of heterocyclic compounds.