Photoswitching of Dextro/Levo Rotation with Axially Chiral Binaphthyls Linked to an Azobenzene

To examine the reversible photoisomerization and subsequent change of asymmetric field, we synthesized optically active 3,3'-disubstituted-1,1'-binaphthyls with an azobenzene moiety. Reflecting the structural change, the specific rotation and circular dichroism underwent significant variations, Under certain conditions, the positive-negative signals were reversible. Furthermore, the magnitude of these changes showed a 3,3'-substituent dependency. Dibenzyloxy or bis(diphenylmethyloxy) derivatives were better suited for sign interconversion of the optical properties. in contrast, the hydroxy group(s) lacked both optical signals and durability.