Berson; Swidler Journal of the American Chemical Society, 1953 , vol. 75, p. 1721,1726 Journal of the American Chemical Society, 1954 , vol. 76, p. 4060,4066 Full Text Show Details Diels; Alder Justus Liebigs Annalen der Chemie, 1931 , vol. 490, p. 257,263 Full Text Show Details Eggelte et al. Tetrahedron, 1973 , vol. 29, p. 2491