Pd-Catalyzed Homo Cross-Dehydrogenative Coupling of 2-Arylpyridines by Using I2 as the Sole Oxidant.

A palladium-catalyzed homo cross-dehydrogenative coupling (CDC) of 2-arylpyridines via C-H activation is described. This reaction employs I2 as the sole oxidant without any other additives, which complements the hypervalent iodine chemistry, such as of phenyliodonium diacetate (PIDA) or IOAc, in C-H activation research field. A tentative mechanism involving a Pd(II)-Pd(IV) catalytic cycle is proposed to rationalize this homo CDC reaction. [ABSTRACT FROM AUTHOR]