Photocycloaddition Reaction of Alkyl-substituted 1,4-Naphthoquinones with Olefins. Substituent Effects on Controlling the Orientation of Cycloaddition Reaction

Article abstract of DOI:10.1246/bcsj.53.757

Photolysis of a benzene solution of 2-alkyl- or 2,3-dialkyl-substituted 1,4-naphthoquinone mixed with an aryl-substituted ethylene afforded 3,4-benzobicyclo<4.2.0>octene-2,5-dione derivatives (cyclobutane type adducts) in a good yield without any other types of products.The orientation of the cycloaddition was likely to control by the adverse van der Waals repulsion of the substituents of the quinone and olefin in addition to the electronic effects of the substituents.The predominant factor orientating the cycloaddition seems to play the van der Waals repulsion due to the substituents both of quinone and olefin.