Partial rate factors in photochemistry: Themetaphotocycloaddition of methylbenzenes to cyclopentene

摘要

AbstractThe partial rate factors of the four modes ofmetaphotocycloaddition of methyl‐substituted benzenes to cyclopentene have been determined by measuring quantum yields of formation of the most importantmetaphotocycloadducts of benzene, toluene and the three xylenes. It is demonstrated that the results can be applied to predict quantum yields of anymetaphotocycloadduct of methylbenzenes to cyclopentene. The predicted yields agree very well with those determined experimentally, and it is shown that the effects of two or more methyl groups are fully additive. The method is promising for the investigation of mechanisms of photochemical reactions and can be used to predict regioselectivitie