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

摘要

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 (MnTPPCl)-T-III/PhIO. In this system, two products obtained (benzaldehyde oxime and N-benzylbenzamide) were not previously described when (MnTPPCl)-T-III was used as catalyst. The change in the oxidant type (PhIO, PhI(OAc)(2), H2O2 or m-CPBA) modified the selectivity for the major product in the presence of (MnTPPCl)-T-III. 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.