One-Pot Synthesis of 2,3-Disubstituted Naphtho[2,3-b]thiophene-4,9-diones from a 2Sulfenyl-1,4-naphthoquinone and Enamines

The title naphthothiophenequinone derivatives were generally synthesized in one-pot using a tandem conjugate addition-cyclization sequence between 2-[2-(ethoxycarbonyl)ethyl]thio-l,4-naphthoquinone and enamines, derived from cyclic and acyclic ketones.