Molybdenum triazolylidene complexes displayed excellent catalytic activity in the synthesis of a wide variety of quinolines through acceptorless dehydrogenative coupling reactions.

Abstract

The first molybdenum triazolylidene complexes catalyzing the atom-economical synthesis of quinolines through acceptorless dehydrogenative coupling of alcohols is reported. A new family of Mo(0) complexes bearing chelating bis-1,2,3-triazolylidene, pyridyl-1,2,3-triazolylidene, and bis-triazole ligands have been prepared and applied as catalysts for the synthesis of quinolines. Interestingly, Mo complexes bearing bis-1,2,3-triazolylidene ligands with alkyl groups (Et, n-Bu) displayed superior catalytic activities than those containing aryl substituents on the triazolylidene rings. Control experiments corroborated that the catalytic reaction involves the dehydrogenation pathway.