Synthesis of 2-trifluoromethyl chromenes via double carbonyl–ene reaction

Abstract

A new protocol for the synthesis of diversely substituted 2-trifluoromethyl chromenes from the cyclization reaction of o-isopropenylphenols with trifluoroacetic anhydride has been developed, which proceeds via sequential trifluoroacetylation and double carbonyl–ene reaction followed by elimination reaction. This methodology exhibits good functional group tolerance, and derivatization of the 2-trifluoromethyl chromene product resulted in other valuable scaffolds.