PHOTOLYSIS OF 2-PHENYLETHYL AND 4-PHENYL-1-BUTYL HALIDES IN ALCOHOLIC SOLVENTS

Article abstract of DOI:10.1016/S0040-4020(01)87368-3

Photolysis of 2-phenylethyl bromide in the lower alcohols gave the corresponding carbinols and ethers as the main products.With 2-phenylethyl iodide, the products were almost exclusively of the latter type, while 4-phenyl-1-butyl halides gave n-butylbenzene, 4-phenyl-1-butene and tetralin.It is shown that each of these products may be assigned to an ionic or radical pathway and that both the nature of the sovent and the structure of the substrate affect the course of photolysis.There is a substrate dependent preference for specific reactions along pathways of both the radical and ionic types.The variations in product composition and distribution are rationalized in terms of the relative efficiencies furnished in these pathways for the relaxation of high energy intermediates produced in the initial stages of photolysis.Intervention by the phenyl group is more pronunced in the case of 2-phenylethyl halides than in the case of the higher homologues and more effective in the ionic pathway.