DABCO-catalyzed three-component reaction for the synthesis of naphtho[2,3-b]thiophene-4,9-diones

Abstract An efficient synthesis of naphtho[2,3- b ]thiophene-4,9-diones has been developed via DABCO-catalyzed three-component reaction of 1,4-naphthoquinone derivatives, α,β -unsaturated ketones and hydrated sodium sulfide. The reaction is initiated by sequential Michael additions of sodium sulfide to α,β -unsaturated ketone and of generated anion to 1,4-naphthoquinone derivative, followed by intramolecular oxidative cyclization and aromatization. Various functional groups in the α,β -unsaturated ketones survive under the reaction conditions and naphtho[2,3- b ]thiophene-4,9-diones are generated in good yields.