43 1,3-ポルオールの立体化学 : 相対配置を決めないで絶対配置を決定する方法(口頭発表の部)

抄録

A general method based on difference circular dichroic spectroscopy for assigning multiple chiral centers in acyclic 1,3-polyols is presented. The validity of this method was demonstrated using 1,2,4,6-tetrols, 1,2,4,6,8-pentols, and 1,2,4,6,8,10,12-heptols as model systems. Sixteen pairs of hydroxy benzoates with a terminal hydroxyl group and the corresponding allylic benzoates were prepared. Subtraction of a CD spectrum of a hydroxy benzoate from that of the paired allylic benzoate gave a difference CD (DIF CD) spectrum, where benzoate/benzoate exciton interactions were canceled. The Cotton effect of the DIF CD spectrum reflects only the exciton interaction of a terminal_allylic benzoate system. A positive sign of the DIF CD is correlated to the (S)-configuration of the allylic position, whereas a negative sign correlated to (R)-configuration. Combination of this DIF CD method and reiterative chemical degradation enables one to determine the absolute configuration of 1,3-polyols, even if the relative stereochemistry is unknown.