TIN-MEDIATED OR MAGNESIUM-MEDIATED DIASTEREOSELECTIVE ALDOL-TYPE REACTIONS FOR THE ASYMMETRIC-SYNTHESIS OF ALPHA-SUBSTITUTED SERINES

Authors
SANO S MIWA T LIU XK ISHII T TAKEHISA T SHIRO M NAGAO Y
Citation
S. Sano et al., TIN-MEDIATED OR MAGNESIUM-MEDIATED DIASTEREOSELECTIVE ALDOL-TYPE REACTIONS FOR THE ASYMMETRIC-SYNTHESIS OF ALPHA-SUBSTITUTED SERINES, Tetrahedron : asymmetry, 9(20), 1998, pp. 3615-3618
Citations number
5
Categorie Soggetti
Chemistry Inorganic & Nuclear","Chemistry Inorganic & Nuclear","Chemistry Physical
Journal title
Tetrahedron : asymmetry → ACNP
ISSN journal
09574166
Volume
9
Issue
20
Year of publication
1998
Pages
3615 - 3618
Database
ISI
SICI code
0957-4166(1998)9:20<3615:TOMDAR>2.0.ZU;2-2
Abstract
Diastereoselective aldol-type reactions of ethyl oxy-2,5-dihydro-5-iso propyl-2-pyrazine-carboxylate (5S)-3 with achiral aldehydes 8a-d was i nvestigated by using Sn(OSO2CF3)(2)-N-ethylpiperizine and MgBr2-trieth ylamine. The reaction with Sn(II) between (5S)-3 and aliphatic aldehyd es 8a,b proved to be quite different from that with Mg(II). On the oth er hand, Sn(II)- or Mg(II)-mediated aldol-type reactions of (5S)-3 wit h benzaldehyde Sc and 3-methyl-2-butenal 8d each afforded the same dia stereomer as the major product. These aldol products were each convert ed to the corresponding alpha-substituted serines 6 and 7 as enantiome rically pure compounds. (C) 1998 Elsevier Science Ltd. AII rights rese rved.