Efficient synthesis of pyridines via a sequential solventless aldol condensation and Michael addition

Abstract

The aldol condensation of an enolisable ketone and a benzaldehyde followed by Michael addition of the enone with a second enolisable ketone under solvent free conditions leads to the quantitative formation of a diketone, which can be readily converted to a pyridine (typically >80% overall yield) via a double condensation in the presence of ammonium acetate in acetic acid, allowing access to a diverse range of oligopyridyls including bipyridyls and terpyridyls.