Synthesis of Functionalized Arenopyrans and Arenylsulfanes by Reacting Nitroallylic Acetates with Arenols and Arenethiols

Abstract

Nitroallylic acetates react with naphthols and electron-rich phenols under mild conditions (TEA, DCM, room temp.) to afford arenopyrans in moderate to excellent yields. Such (3+3) annulation of a 1,3-bielectrophilic nitroallylic acetate and a 1,3-binucleophilic arenol involving an SN2′ reaction and an intramolecular 6-endo-trig cyclization takes place in a regio- and stereoselective manner. Surprisingly, the reaction of arenethiols under the same conditions provided nitroallylic thioethers instead of the expected arenothiopyrans presumably through a direct SN2 reaction.