Convenient One-Pot Three-Component Synthesis of Trifluoromethylated Tetrahydrobenzo[g]chromene Derivatives

A series of ethyl 4-(het)aryl-5,10-dioxo-2-hydroxy-2-(trifluoromethyl)-3,4,5,10-tetrahydro-2H-benzo[g]chromene-3-carboxylates were efficiently synthesized from 2-hydroxynaphthoquinone, aromatic aldehydes, and ethyl 4,4,4-trifluoro-3-oxobutanoate by a one-pot multicomponent reaction catalyzed by the combination of ammonium acetate and acetic acid. The benzo-chromenes are presumably formed through an initial Knoevenagel condensation followed by a Michael addition and regioselective intramolecular annulation. The dehydration reaction of the hemiketal moiety to the corresponding dehydrated product was also studied.