Dual Catalysis in Domino N-Benzylation/Intramolecular C-H Arylation: Regio- and Chemoselective Synthesis of Annelated Nitrogen Heterocycles

A general method has been developed for the synthesis of fused nitrogen heterocycles by using a domino N-benzylation/C-H arylation reaction sequence. The details and yields of the domino process were compared with those of the two-step literature protocol. Fused azaindoles, which are otherwise difficult to obtain, were synthesized by using this process. The unprecedented catalytic role of PPh3 in this N-benzylation is described.