Studies of chemoselectivity in Diels–Alder reactions of 2-(p-tolylsulfinyl)-1,4-benzoquinone and styrenes: formation of (p-tolylsulfinyl)-1,4-phenanthrenequinones
作者:M.Carmen Carreño、Antonio Urbano
DOI:10.1016/s0040-4039(00)00593-1
日期:2000.5
Diels-Alder reactions of 2-(p-tolylsulfinyl)-1,4-benzoquinone 1 with 4-methoxystyrenes 2a-b in polar solvents afforded 2- and 3-(p-tolylsulfinyl)-1,4-phenanthrenequinones 4a-b and 5a-b as major compounds. A second cycloaddition of 5a and 4a with 3,4-dimethoxystyrene 2a gave access to C- and S-shaped pentacyclic molecules 10 and 11 in a highly regioselective way. (C) 2000 Elsevier Science Ltd. All rights reserved.