Dj. Tantillo et al., Origins of stereoselectivity in intramolecular Diels-Alder cycloadditions of dienes and dienophiles linked by ester and amide tethers, J ORG CHEM, 66(6), 2001, pp. 1938-1940
B3LYP/6-31+G(d) calculations of structures and relative energies for compet
ing transition states for intramolecular Diels-Alder reactions of substitut
ed 3,5-hexadienyl acrylates and acrylamides show that boatlike conformation
s are sometimes favored in the forming ring that includes the tether.