Cobalt-catalyzed intramolecular C-H amination with arylsulfonyl azides.

Cobalt complexes of porphyrins are effective catalysts for intramolecular C-H amination with arylsulfonyl azides. The cobalt-catalyzed process can proceed efficiently under mild and neutral conditions in low catalyst loading without the need of other reagents or additives, generating nitrogen gas as the only byproduct. The catalytic system can be applied to primary, secondary, and tertiary C-H bonds and is suitable for a broad range of arylsulfonyl azides, leading to high-yielding syntheses of various benzosultams.