LAUSR

A catalyst-free direct aerobic oxidative annulation reaction of 2-aminobenzylic amines and α- hydroxyl ketones can efficiently afford the versatile 5 H -1,4-benzodiazepine derivatives by employing air as the economic and green oxidant under mild conditions. Interestingly, solvent was found to be crucial to the reaction, so that by using acetic acid as the best solvent, an efficient and practical method can be achieved, requiring no catalysts or additives at all. This method tolerates a wide range of 2-aminobenzylic amines and α- hydroxyl ketones, can be scaled up to multigram synthesis and directly applied in one-step synthesis of the pharmaceutically-active N- desmethylmedazepam derivatives, revealing the potential of this new method in the synthesis of 5 H -1,4-benzodiazepine skeleton-based pharmaceuticals and chemicals.