Annulation of 2,3-diphenyl-4H-chromen-4-ones via photo-induced hydrogen evolution

Abstract

An efficient photo-induced transition-metal-free direct hydrogen evolution and annulation of 2,3-diphenyl-4H-chromen-4-ones in EtOH–H₂O (19 : 1, v/v) at room temperature was described. The reported methodology provided a quick and easy access to the synthesis of dibenzo[a,c]xanthen derivatives, which eliminates the use of any catalysts, oxidants and additives.