Iron-catalysed quinoline synthesis via acceptorless dehydrogenative coupling

Abstract

An atom-economical and straightforward methodology for the synthesis of quinolines from α-2-aminoaryl alcohols and secondary alcohols is presented. Using the Earth-abundant and air-stable iron catalyst under activating agent (such as NaBHEt₃) free conditions, this acceptorless dehydrogenative coupling provides quinolines with high yields and good functional group tolerance. Importantly, the described protocol allows for secondary α-2-aminoaryl alcohols and β-substituted secondary alcohols, thus readily affording highly substituted fused polycyclic quinolines. Moreover, 39 substituted quinolines were prepared in up to 94% isolated yields by using this iron catalysis.