Heterodienophiles—V : A stereochemical study of aldimine-diene cycloadditions

Abstract A study has been made of exo/endo ratios in the formation of azabicyclics via cycloadditions of cyclopenta- or cyclohexa-1,3-diene with N-carbethoxy and N- p -toluenesulfonyl trichloromethyl imines, N- p -toluenesulfonyl trifluoromethyl imine, and N-phenyl-5-methoxyhydantoin. For N-carbethoxy imines both thermal and acid catalyzed cycloadditions were investigated with acid catalysis being notably evident. Cyclic Z -imines afford endo adducts while acyclic imines afford exo/endo mixtures.