A molybdenum-catalyzed acceptorless dehydrogenative approach for quinoline synthesis using amino alcohol

We report the bidentate-phosphine-ligand-based molybdenum π-allyl complex [Mo(CO)₂(η³-C₃H₅)(DPPE)Cl] (Mo-1; DPPE = 1,2-bis(diphenylphosphino)ethane) for the dehydrogenative annulation of 2-aminobenzyl alcohol with a wide variety of methylketones to form N-heterocycle quinoline derivatives. The complex Mo-1 also catalyzed the formation of substituted quinolines through the reaction of 2-aminobenzyl alcohol with 1-phenylethanol derivatives. This methodology demands low loading of the complex (1 mol%) and a catalytic base. The process produces water and hydrogen gas as the only byproducts. Thus, the reactions are atom-efficient and environmentally benign.