Chapter 9: Palladium-catalyzed Decarboxylative Couplings

Palladium-catalysed decarboxylative couplings have recently emerged as new and important synthetic strategies that find versatile applications in the construction of carbon–carbon and carbon–heteroatom bonds. In this reaction-type, the organometallic species are formed via extrusion of carbon dioxide from metal carboxylates and subsequently incorporated into different coupling reactions with other organic compounds. As a result, the coupling takes place regioselectively at the decarboxylation site, and thereby the carboxylate acts as leaving group and the only by-product is carbon dioxide. In this chapter, we describe the inventive process that led to the discovery of the first active catalyst systems for the decarboxylative biaryl synthesis and the stepwise extension to a broadly applicable synthetic concept. We cannot hope to provide a comprehensive or even a particularly representative sampling of this diverse and highly active research. As several excellent review articles have been published on various aspects of this field, our goal is to cover enough background and insight to help the reader appreciate the potential of this novel strategy.