Reagent Design and Study of p-Benzoquinone Derivatives. The Site-Selective Cycloaddition Reaction of Diquinones and Photochemical Cage Formation of the Adducts

Article abstract of DOI:10.1021/jo00332a016

Cycloaddition reactions of naphthodiquinone derivatives and the photochemical behavior of their adducts have been investigated.Naphthodiquinone (4) and dichloronaphthodiquinone (5) reacted exclusively at the internal double bond with both cyclopentadiene and quadricyclane to give the corresponding 1:1 adducts in high yields.While anthradiquinone (6) reacted also only at the internal double bond with quadricyclane, the reaction with cyclopentadiene took place at both the internal and terminal double bonds of 6.The stereochemistry of the adducts was determined by spectral inspections and chemical transformations.The cyclopentadiene adducts were photochemically converted into the cage compounds in high yields, although the quadricyclane adducts were photoinert.In the photochemical reactions, high site selectivity was observed; the intramolecular <2+2> ? photoaddition occurred only between enedione (electron poor) and cyclopentene (electron rich) double bonds.