Kinetic resolution of the racemic 2-hydroxyalkanoates using the enantioselective mixed-anhydride method with pivalic anhydride and a chiral acyl-transfer catalyst.
Kinetic resolution of the racemic 2-hydroxyalkanoates using the enantioselective mixed-anhydride method with pivalic anhydride and a chiral acyl-transfer catalyst.
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DOI：
10.1002/chem.200902257
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发表时间：
2010-01
期刊：
影响因子：
--
通讯作者：
Isamu Shiina;Kenya Nakata;K. Ono;Masuhiro Sugimoto;Akihiro Sekiguchi
中科院分区：
文献类型：
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作者：
Isamu Shiina;Kenya Nakata;K. Ono;Masuhiro Sugimoto;Akihiro Sekiguchi
A variety of optically active 2-hydroxyalkanoates and the corresponding 2-acyloxyalkanoates are produced by the kinetic resolution of racemic 2-hydroxyalkanoates by using achiral 2,2-diarylacetic acid with hindered carboxylic anhydrides as the coupling reagents. The combined use of diphenylacetic acid, pivalic anhydride, and (+)-(R)-benzotetramisole ((R)-BTM) effectively produces (S)-2-hydroxyalkanoates and (R)-2-acyloxyalkanoates from the racemic 2-hydroxyalkanoates (s-values=47-202). This protocol directly provides the desired chiral 2-hydroxyalkanoate derivatives from achiral diarylacetic acid and racemic secondary alcohols that do not include the sec-phenethyl alcohol moiety by using the transacylation process to generate the mixed anhydrides from the acid components with bulky carboxylic anhydrides under the influence of the chiral acyl-transfer catalyst. The transition state that provides the desired (R)-2-acyloxyalkanoate from (R)-2-hydroxyalkanoate included in the racemic mixture is disclosed by DFT calculations, and the structural features of the transition form are also discussed.
