A novel cyclodehydration: the acid-catalysed conversion of α-(4-ethoxynaphth-1-yl)benzoin into 1,2-diphenyl-5-ethoxynaphto-[2,1-b]furan

Abstract

α-(4-Ethoxynaphth-1-yl)benzoin with stannous chloride and hydrochloric acid in hot glacial acetic acid was not reduced to benzoyl(4-ethoxynaphth-1-yl)phenylmethane as expected, but was cyclised to 1,2-diphenyl-5-ethoxynaphtho[2,1-b]furan. This cyclisation was also effected with sulphuric acid, alone or in glacial acetic acid, and with anhydrous aluminum chloride in anisole. A mechanism for the cyclodehydration process is proposed. The reduction of α-(4-ethoxynaphth-1-yl)benzoin to benzoyl(4-ethoxynaphth-1-yl)phenylmethane is described.