Departamento de Quhica Orgcinica, Escuela Nacional de Ciencias BiolGgicas, IPN, Carpio y Plan de Ayala, I1340 Mexico, DF, MGxico, In+t de Chimie Organique de l'Uniuersit6, CH 1005 Lausanne, Switzerland, and Instituto de Quimica, UNAM, Ciudad Uniuersitaria, 04510, Mexico, DF, MGxico ... Thermal Diels-Alder cycloadditions of captodative olefins 1-acetylvinyl arenecarboxylates, CH2=C(COC- H3)0COAr, la (Ar = CsH4pNO2), lb (AI = a-naphthyl), ...