Solvent-Dependent cis-trans One-Way Photoisomerization of Bisformyl-Substituted 1,6-Diphenyl-1,3,5-hexatriene

Abstract trans,trans,trans-1,6-Bis(p-formylphenyl)-1,3,5-hexatriene underwent stereoselective photoisomerization to give its cis,trans,trans isomer regardless of the solvent polarity. Quantum yields of trans,trans,trans-to-cis,trans,trans isomerization decreased dramatically with decreasing solvent polarity, whereas those of the reverse reaction gradually increased. This led to the cis,trans,trans-to-trans,trans,trans ‘one-way’ isomerization in nonpolar solvents.