Pericyclic Reaction of Cyclopentadienones with Nonconjugated Dienes. Formation of Double Diels-Alder Adducts
Pericyclic reactions of 2,5-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone (Ia) with nonconjugated dienes (IIa-g) were investigated.The cyclopentadienone (Ia) reacted readily with IIa-g to give Π cycloadducts (IIIa-g) that lost carbon monoxide to