High-pressure-assisted addition of (methoxyphenyl)maleic anhydrides to dienes. Synthesis of 3a-aryltetrahydroisoindole-1,3-diones

A new synthesis of (2-and 4-methoxyphenyl)maleic anhydrides was accomplished, the reactions of which with cyclopentadiene and 3-sulfolene, serving as a 1,3-butadiene equivalent, furnished the [4+2]-cycloadducts. The latter were converted into imides of 2-aryl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic and 1-arylcyclohex-4-ene-1,2-dicarboxylic acids respectively.