Photochemical Reactions of Model cis-Stilbenes: The -Cycloaddition Reaction

Article abstract of DOI:10.1021/jo00242a033

The photochemical <2 + 2>-reactions of three model cis-stilbenes have been examined. 1,2-Diphenylcyclobutene was found to undergo photochemical <2 + 2 >-cycloaddition reactions with 2,5-dimethyl-2,4-hexadiene and with itself but did not undergo reaction with tetramethylethylene. 1,2-Diphenylcyclopentene and 1,2-diphenylcyclohexene were unreactive in photochemical <2 + 2>-cycloaddition reactions.The singlet excited-state lifetimes of these compounds were measured.The results show that the observation of the cis-stilbene <2 + 2>-reaction is dependent upon the rate of deactivation of the excited state.