An efficient synthesis of isoquinolines via rhodium-catalyzed direct C-H functionalization of arylhydrazines.

A highly efficient rhodium-catalyzed C-H activation of arylhydrazines and coupling with internal alkynes has been realized under mild conditions. The isoquinolines have been prepared in moderate to excellent yields in high efficiency. This methodology features the use of readily available starting materials, and a simple hydrazine moiety as a directing group, in the absence of an external metal co-oxidant under an air atmosphere. The C-H bond activation and the N-N bond cleavage have been successively realized under mild conditions.