General Description

1,3-Cyclooctadiene, particularly its (Z,Z)-isomer, can undergo enantiodifferentiating photoisomerization to produce chiral (E,Z)-1,3-cyclooctadiene with significant enantiomeric excess (up to 18% ee) when sensitized by chiral aromatic carboxylates, such as (-)-menthyl benzenehexacarboxylate, in nonpolar solvents. The process is highly sensitive to solvent polarity, with polar solvents diminishing enantioselectivity, likely due to radical ionic intermediates. The resulting optically active (E,Z)-isomer exhibits exceptionally high specific rotation and circular dichroism, confirming theoretical predictions about its chiroptical properties. Supramolecular systems, such as γ-cyclodextrin-based rotaxanes, further enhance enantioselectivity (up to 15.3% ee) by providing chiral binding sites for sensitization.