The photochemistry of 4-phenylbut-1-ene

Photolysis of 4-phenylbut-1-ene in the gas phase results in the formation of benzylcyclopropane, trans-phenyl-methylcyclopropane, and trans-1-phenylbut-2-ene. By the use of butene, piperylene, and neopentane quenching experiments and by fluorescence measurements, the formation of the products is shown to occur via the triplet manifold and to involve a common vibrationally excited intermediate. In solution 4-phenylbut-1-ene produces no new monomeric compound on excitation in the aromatic absorption band.