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Communication | Special issue | Vol 82, No. 2, 2010, pp.1171-1180
Published online, 1st November, 2010
DOI: 10.3987/COM-10-S(E)120
Kinetic Resolution of the Racemic 1-(Aryloxazol-2-yl)carbinols with Achiral Carboxylic Acids by Asymmetric Esterification: A New Method for the Preparation of Chiral 1,2-Amino Alcohols

Kenya Nakata, Keisuke Ono, and Isamu Shiina*

*Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo 162-8601, Japan

Abstract

An efficient kinetic resolution of racemic 1-(aryloxazol-2-yl)carbinols with achiral carboxylic acids using pivalic anhydride in the presence of (R)-benzotetramisole ((R)-BTM) is reported. It was determined that the naphth[1,2-d]oxazole moiety at the C-1 position in the alcohols is a suitable structure to attain a high selectivity. An application to produce optically pure 1,2-amino alcohols was developed by the kinetic resolution of the racemic 1-(aryloxazol-2-yl)carbinols followed by a two-step cleavage of the aryloxazole part to form the corresponding amino group. Transition states that provide the desired (R)-esters from (R)-1-(benzoxazol-2-yl)ethan-1-ol or the undesired (S)-esters from (S)-1-(benzoxazol-2-yl)ethan-1-ol are disclosed by DFT calculations. Another transition state that affords the desired (R)-ester from (R)-1-(naphth[1,2-d]oxazol-2-yl)ethan-1-ol included in the racemic mixture is also estimated, and the structural features of these transition states are discussed.