Dynamic control of racemization rate through E-Z 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.