Photoreactions of halogenobenzenes with cyclopentene. Insertion into carbon–halogen bonds

Abstract

Chloro-, bromo-, and iodo-benzenes photoreact with cyclopentene to give, principally, products derived from insertion into the C–halogen bond, a type of reaction hitherto unknown in this series, but fluorobenzene mainly forms meta- and para-cycloadducts with only a minor proportion of the cis-insertion product.