LEWIS-ACID-MEDIATED AND CATIONIC LITHIUM-MEDIATED DIASTEREOSELECTIVE ALDOL-TYPE REACTION-BASED ON A DOUBLE CHIRAL RECOGNITION MANNER FOR THE ASYMMETRIC-SYNTHESIS OF ALPHA-SUBSTITUTED SERINES

被引:27
作者
SANO, S
LIU, XK
TAKEBAYASHI, M
KOBAYASHI, Y
TABATA, K
SHIRO, M
NAGAO, Y
机构
[1] UNIV TOKUSHIMA,FAC PHARMACEUT SCI,TOKUSHIMA 770,JAPAN
[2] RIGAKU CORP,AKISHIMA,TOKYO 196,JAPAN
关键词
D O I
10.1016/0040-4039(95)00725-R
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Diastereoselective aldol-type reaction of ethyl (5R or 5S)-3,6-diethoxy-2,5-dihydro-5-isopropyl-2-pyrazinecarboxylate (5) with chiral aldehyde 7 was investigated by using Sn(OSO2CF3)(2)-N-ethylpiperizine, MgBr2-Et(3)N, n-butyllithium, and lithium diisopropylamide. The mediation mode with Sn(II) between (5R or 5S)-5 and 7 proved to be quite different from that with Mg(II). The two aldol products were converted to the corresponding gamma-lactonic alpha-substituted serines (2S)- and (2R)-10.
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页码:4101 / 4104
页数:4
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