Palladium(II)-Catalyzed Dehydrogenative Cross-Coupling between Two C_(sp~3)-H Bonds: Unexpected C=C Bond Formation

摘要

Developing efficient synthetic methods for the formation of carbon-carbon bonds is crucial for organic synthesis. In recent years, transition-metal-catalyzed C_(sp)~3)—H functionalization to forge C(sp)~3)-C(sp)~3) C(sp)~3)—C(sp)~3), and C(sp)~3)-C(sp)~3) bonds has attracted much attention.(sp)~3) From the step-economic and academic perspective, the dehydrogenative cross-coupling of sp~3-hy-bridized C—H bonds with other C-H bonds is one of the most attractive, yet most challenging, methods of carbon-carbon bond construction without the need for time-consuming prefunctionalization of both substrates. Lately, the dehydrogenative cross-coupling of a-C(sp)~3)-H bonds of amines, ethers, allylic and benzylic groups, and alkane C(sp)~3)-H bonds with a wide range of C(sp)~3)-H bonds has evolved into a powerful strategy for forming new C(sp)~3)-C(sp)~3) bonds (Scheme 1 a). These