Modulation of ?-Facial Selectivity in Diels-Alder Cycloaddition to Isodicyclopentafulvenes by Remote Para Substitution of an Exocyclic Phenyl Group

Article abstract of DOI:10.1021/jo00243a054

Isodicyclopentafulvenes that carry an exocyclic para-substituted phenyl group as in 3 enter into Diels-Alder cycloaddition with highly reactive dienophiles exclusively from below-plane.The situation with the more sterically hindered and less reactive reagent (Z)-1,2-bis(phenylsulfonyl)ethylene is one where addition occurs from both faces.