Competition for Regiochemical Control between Substituents of Some 2,3-Disubstituted Buta-1,3-dienes in the Diels-Alder Reactions
Several 3,4-disubstituted 3-sulfolenes 1a-j, the precursors for the corresponding 2,3-disubstituted 1,3-dienes 2a-j, are conveniently prepared and undergo Diels-Alder reactions smoothly with methyl acrylate under thermal conditions where the order of para