Structural determination of coumarin derivatives. Diels-Alder adducts using 3-methylene-2,4-chromanedione as trapping agent

With a series of unsatured compounds, 3-methylene-2,4-chromanedione can behave as ambident heterodiene or as dienophile affording the hetero-Diels-Alder and Diels-Alder adducts, respectively. The structural analysis aimed at identifying the peculiar spectral parameters of these adducts, has been performed via multidimensional NMR experiments supported by Molecular Mechanics calculations.