Iron-catalysed quinoline synthesis via acceptorless dehydrogenative coupling

An atom-economical and straightforward methodology for the synthesis of quinolines from alpha-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 alpha-2-aminoaryl alcohols and beta-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.

Automated summary

An atom-economical and straightforward methodology for the synthesis of quinolines from alpha-2-aminoaryl alcohols and secondary alcohols is described. This protocol uses an Earth-abundant and air-stable iron catalyst under activating agent-free conditions, resulting in high yields and good functional group tolerance. Notably, the method allows for the synthesis of highly substituted fused polycyclic quinolines using secondary alpha-2-aminoaryl alcohols and beta-substituted secondary alcohols, achieving up to 94% isolated yields.