Dehydrogenative C(sp)-H bond functionalization of tetrahydroisoquinolines mediated by organic oxidants under mild conditions

The organocatalyzed Mannich reaction of unsubstituted and N -aryl-substituted tetrahydroisoquinolines (THIQs) and the Strecker reaction of several N -aryl-substituted THIQs through dehydrogenative C(sp3)-H bond functionalization (cross-dehydrogenative coupling) promoted by organic single electron oxidants DDQ and IBX are presented. The C-H oxidation/Mannich reaction of less reactive N -aryl substituted pyrrolidines is achieved via metal catalyzed photoredox catalysis. Operationally simple procedures provide desired products in an effective and time preserving manner. DDQ and IBX are effective SET oxidants of N -aryl-protected and unprotected THIQs. Mannich and Strecker type functionalizations ensued in an overall CDC reaction.