2009 | Xiao Chen, Keary M. Engle, Dong-Hui Wang, and Jin-Quan Yu
This review discusses the development and versatility of palladium-catalyzed C–H activation/C–C bond-forming reactions, focusing on Pd(II)-catalyzed processes. It begins with an overview of four major catalytic cycles: Pd(II)/Pd(0), Pd(II)/Pd(IV), Pd(0)/Pd(II)/Pd(IV), and Pd(0)/Pd(II). The review then delves into recent advancements in Pd(II)-catalyzed coupling of C–H bonds with organometallic reagents through a Pd(II)/Pd(0) catalytic cycle. Despite significant progress, improving the versatility and practicality of these reactions remains a challenge. The review highlights the importance of directing groups and the role of coordination chemistry in enhancing reactivity. It also discusses the expansion of substrate scope, including the use of simple functional groups like carboxylic acids and alcohols, and the development of enantioselective variants. Finally, the review outlines key challenges and potential solutions for future improvements in this field.This review discusses the development and versatility of palladium-catalyzed C–H activation/C–C bond-forming reactions, focusing on Pd(II)-catalyzed processes. It begins with an overview of four major catalytic cycles: Pd(II)/Pd(0), Pd(II)/Pd(IV), Pd(0)/Pd(II)/Pd(IV), and Pd(0)/Pd(II). The review then delves into recent advancements in Pd(II)-catalyzed coupling of C–H bonds with organometallic reagents through a Pd(II)/Pd(0) catalytic cycle. Despite significant progress, improving the versatility and practicality of these reactions remains a challenge. The review highlights the importance of directing groups and the role of coordination chemistry in enhancing reactivity. It also discusses the expansion of substrate scope, including the use of simple functional groups like carboxylic acids and alcohols, and the development of enantioselective variants. Finally, the review outlines key challenges and potential solutions for future improvements in this field.