REGIOSELECTIVITE DE LA CYCLOADDITION DIPOLAIRE-1,3. REACTIONS DE DIBENZO-2,3:6,7 HEPTAFULVENES AVEC QUELQUES DIPOLES

Article abstract of DOI:10.1016/S0040-4020(01)91261-X

The addition of several 1,3-dipoles, viz. diazoalkanes, parachloro-benzonitrile oxide and azomethine ylides, to 2,3:6,7-dibenzo-heptafulvenes, occurs exclusively at the endocyclic double bond, leading respectively to pyrazolines, isoxazolines and pyrrolidines.This regiospecificity is due to steric factors which are conveniently discussed using Sustmann's variation perturbation theory.