[2 + 2] Cycloaddition of two CN double bonds. First structural evidence for head-to-tail photodimerization in the 2-phenylbenzoxazole series

Abstract

Irradiation of 2-(4-fluorophenyl)benzoxazole in a two-phase medium leads to crystals of the [2 + 2] photoadduct; the head-to-tail structure of this dimer has been demonstrated by an X-ray study.