One pot oxidative N-S bond formation to access 2-sulfenylimine chromenes

The synthesis of 2-sulfenylimine chromene compounds (8) is accomplished by reacting benzaldehyde (1), malanonitrile (2) and dimedone (3) followed by sequential addition of N-chlorosuccinimide and thiophenols to the in situ formed 2-amino-4(H) chromenes (4) in a one pot, catalyst free, five component reaction in toluene medium. When aniline was employed as the nucleophile in place of thiophenol, the formation of hexahydrobenzofuran-2-N-phenyl carboxamide derivatives (5) was observed. Excellent yields, simple reaction conditions and high compatibility are the advantages of this protocol.