Divergent Synthesis of Benzene Derivatives: Brønsted Acid Catalyzed and Iodine-Promoted Tandem Cyclization of 5,2-Enyn-1-ones

Highly substituted benzene derivatives, including alkoxy-, iodoalkoxy-, and diiodo-substituted benzenes, can be selectively synthesized via Brønsted acid catalyzed and iodine-promoted tandem carbocyclization respectively. This reaction involved a direct process for C-C bond formation from 5,2-enyn-1-ones, and different reaction systems (Brønsted acids/electrophiles with solvents) afforded different substituted benzenes. Furthermore, the halogenated moiety and alkoxy group can be readily introduced into the benzene in a position which has not been easily obtained previously.