The first examples of Diels-Alder cycloaddition reactions of 6-substituted 1-(p-nitrobenzoyl)-5,6-dihydro-2-pyridinones are described. This reaction benefits from the fact that the diene adopts an endo orientation trans to the axial substituent at C-6 due to A(1.3) allylic type strain with the N-PNB protecting group.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.1100104