Practical enantioresolution of alcohols with 2-methoxy-2-(1-naphthyl)propionic acid and determination of their absolute configurations by the (1)H NMR anisotropy method.
The enantioresolution of racemic alcohols as esters of 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid 1) and the determination of their absolute configurations on the basis of (1)H NMR anisotropy effect are described. The enantiopure MalphaNP acid (S)-(+)-1 was allowed to react with racemic 2-alkanols and 1-octyn-3-ol, yielding diastereomeric mixtures of esters, which were easily separated by HPLC on silica gel. To determine the absolute configurations of the first-eluted diastereomeric esters by the (1)H NMR anisotropy method, the general scheme was proposed. Separated esters were reduced with LiAlH(4) or hydrolyzed with KOH/EtOH to recover enantiopure alcohols.
Taji
Hiromi
H
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahara, Aoba, Sendai 980-8577, Japan.
Kasai
Yusuke
Y
Sugio
Akinori
A
Kuwahara
Shunsuke
S
Watanabe
Masataka
M
Harada
Nobuyuki
N
Ichikawa
Akio
A