Catalyst- and solvent-free approach to 2-arylated quinolines via [5 + 1] annulation of 2-methylquinolines with diynones.

A novel route for the synthesis of 2-arylated quinolines through a [5 + 1] annulation directly from 2-methylquinolines and diynones under catalyst-free and solvent-free conditions was disclosed. This synthetic process was atom-economic, with good tolerance of a broad range of functional groups, and with great practical worth.