Manganese-catalyzed dehydroxyamination of catechols for the synthesis of redox-active and heterocyclic scaffolds

Abstract

A catalytic protocol employing manganese(II) nitrate [Mn(NO₃)₂] has been developed for the selective C–O bond cleavage of catechols, enabling subsequent C–N bond formation. This transformation offers a versatile approach to the synthesis of 2-(arylamino)phenols, dihydrobenzo[d]oxazoles, and benzoxazoles under mild conditions. Aromatic amines such as anilines reacted smoothly to afford 2-(arylamino)phenols in excellent yields. In the presence of ketones, the methodology was further extended to the efficient synthesis of novel dihydrobenzo[d]oxazole derivatives. In contrast, the use of aliphatic amines directly led to benzoxazole products, with the corresponding 2-(alkylamino)phenol intermediates not being observed under the optimized conditions. This Mn(II)-catalyzed strategy demonstrates broad substrate scope and high selectivity, offering a practical route to valuable N-heterocyclic scaffolds.