Synthesis of Optically Active Spiro Compounds with a 3,3′-(4H,4′H)-Spirobi(2H-naphtho[1,2-b]pyran) Skeleton and Their Applications as Chiral Dopants for Nematic Liquid Crystals

Chiral dopants with a spiro structure for nematic liquid crystals were synthesized from optically active 3,3'-(4H,4'R)-spirobi(2H-naphtho[1,2-b]pyran)-6,6'-dicarboxylic acid, and their helical twisting power (HTP) values were evaluated. Chiral dopants having the S configuration induced minus helices in the host nematic liquid crystals. It was found that the novel ester-linked spiro chiral dopants exhibited large molar HTP values. In particular, a chiral dopant with two pyrimidine structures in the side chain moiety showed the highest molar HTP value of 62.1 μm -1 mol -1 kg. In contrast, ether-linked chiral dopants showed relatively small molar HTP values.