Cyclohexenone derivatives. Part VII. Novel aromatisation reaction of some aryloxocyclohexenylacetic acid derivatives

Abstract

Methyl 2-aryl-6-oxocyclohex-1-enylacetates (I; R = Me) and some related compounds, when heated with a number of base–solvent systems, undergo aromatisation, the cyclohexenone system becoming phenolic with concomitant loss of the acetate side-chain. Sodium hydride in dimethylformamide at 100° is most effective for this transformation, and few alkoxides in aprotic solvents also catalyse the reaction. The mechanism is discussed. The results of dehydrogenation using pyridine hydrochloride are also reported.