Palladium‐Catalyzed Picolinamide‐Directed Benzylic C(sp3)−H Chalcogenation with Diaryl Disulfides and Diphenyl Diselenide.

The first palladium‐catalyzed direct benzylic C(sp3)−H chalcogenation with diaryl disulfides and diphenyl diselenide has been established. The coupling reaction proceeds between the thioether radical and palladiumcycle intermediate. Picolinamide serves as an excellent directing group for the C−H activation of benzylic C(sp3)−H and can be easily removed. The current protocol exhibits a relatively broad substrate scope and high functional group compatibility. A mechanistic study indicates that palladium(IV) intermediate is probably formed during the course of the reaction. [ABSTRACT FROM AUTHOR]