Conformational studies about the NN′ bond by NMR spectroscopy and their application in the configurational assignment to the Diels-Alder adducts of maleic annhydride

Article abstract of DOI:10.1016/S0040-4020(01)97106-6

Non-planar stable conformations about the NN′ bond in N-(diacylamino)imide derivatives of naphthalene-maleic anhydride adducts 2 and 3 and their reduced products 4 and 5 have been studied by NMR spectroscopy and have been demonstrated as a means of assigning exo/endo configurations to the Diels-Alder adducts. While N-(diacetylamino)imide system has proven to be a suitable probe for configurational assignment to Diels-Alder adducts, which show clear cut magnetic effects on the N′-substituents, the N′-acetyl-N′-aroyl-N-aminoimide system has been shown to be a versatile probe, applicable even to simple adducts. The N-(diaroylamino) imide system has shown little effect on the cage-protons, whereby it has been presumed that the aryl-rings of the N′-aroyl groups preferably reside away from the cage-moiety.