Unexpected Products of Benzylamine Oxidation Catalyzed by Manganese Porphyrins: Some Factors that Play a Critical Role for Imine Formation

Abstract This work describes the oxidation of benzylamine by PhIO, catalyzed by a series of first‐row metal salts and the respective first‐, second‐, and third‐generation metalloporphyrins. Five products were identified in reactions with [Mn III TPPCl]/PhIO. In this system, two products obtained (benzaldehyde oxime and N ‐benzylbenzamide) were not previously described when [Mn III TPPCl] was used as catalyst. The change in the oxidant type (PhIO, PhI(OAc) 2 , H 2 O 2 or m ‐CPBA) modified the selectivity for the major product in the presence of [Mn III TPPCl]. For a second‐generation manganese porphyrin, the highest total yield was observed (99%), with 72% of imine product and only 1% of catalyst destruction, even in homogeneus system.