On the Mechanism of Palladium‐Catalyzed Unsaturated Bond Transformations: A Review of Theoretical Studies

Palladium‐catalyzed transformation reactions of unsaturated molecules have considerable importance because of their versatility and wide range of applications. Over the past decades, various experimental studies on palladium‐catalyzed unsaturated bond transformation have been reported, and mechanistic and computational studies have also progressed considerably. With the development of computing methods and power, theoretical calculation has become a powerful tool for mechanistic study of transition‐metal catalysis. In this review, we summarize the literature on mechanistic studies of palladium‐catalyzed transformations of unsaturated molecules, including hydrogenation, alkylation, arylation, silylation, vinylation, cyclization and esterification. Mechanistically, most of these reactions undergo a redox pathway, involving either oxidative addition, insertion, transmetalation, β‐H elimination or reductive elimination. Some instead undergo a non‐redox pathway, mainly involving insertion or β‐H elimination.