an arylsubstituted 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
2-烷基-或2,3-二烷基-取代的
1,4-萘醌与芳基取代的
乙烯混合的苯溶液的光解得到3,4-苯并双环[4.2.0]
辛烯-2,5-二酮衍
生物(
环丁烷型)加合物)在没有任何其他类型的产品的情况下以良好的产量。除了取代基的电子效应外,环加成的取向可能还受到醌和烯烃取代基的不利范德华排斥作用的控制。由于醌和烯烃的取代基,定向环加成的主要因素似乎起到范德华排斥作用。