The addition of simple aromatic hydrocarbons to condensed aromatic thiophenes promoted by aluminum chloride. Part II. Naphtho[1,2-b]thiophene

The reaction of naphtho[1,2-b]thiophene with an aromatic hydrocarbon in the presence of aluminum chloride at 20 °C gave either a 3-aryl-2,3-dihydronaphtho[1,2-b]thiophene by addition to the 2,3-bond or 2,3-dihydronaphtho[1,2-b]thiophene as a result of hydride abstraction.Occasionally 2-aryl-2,3-dihydronaphtho[1,2-b]thiophenes were obtained. At higher temperatures 2-arylnaphtho[1,2-b]thiophenes and 2,3-dihydronaphtho[1,2-b]thiophene were isolated. Attempts are made to rationalize the formation of these products in terms of protonation of naphtho[1,2-b]thiophene by moist aluminum chloride and reaction of the resulting electrophile with an aromatic substrate.