Synergy between heterogeneous catalysis and microwave irradiation in an efficient one-pot synthesis of benzene derivatives via ring-opening of Diels-Alder cydoadducts of substituted furans

The use of silica-supported Lewis acids as catalysts under microwave irradi ation promotes regiospecific opening of the 7-oxa bridge of Diels-Alder cyc loadducts, producing the corresponding arenes in a single step. This rapid and efficient procedure permits the synthesis of 1,2-. 1,2,4- and 1,2,3,4-s ubstituted benzenes by reaction of 2,5-dimethylfuran (1), 2-methoxyfuran (2 ) and 2-ethylfuran (3) with dienophiles such as acrylonitrile, methyl acryl ate, N-methylmaleimide and fumaronitrile.