Dynamic Control of Racemization Rate through <i>E</i><i>−</i><i>Z</i> Photoisomerization of Azobenzene and Subsequent Partial Photoresolution under Circular Polarized Light

We have synthesized bicyclic azobenzene dimers that possess enantiomers whose racemization rates could be controlled reversibly through E−Z photoisomerization of the azobenzene units. Upon alternating the exposure to r- and l-CPL, we were able to repeatedly perform partial enrichment of (S)- and (R)- enantiomers, respectively.