ADDITION OF 2-LITHIOFURAN TO CHIRAL ALPHA-ALKOXY NITRONES - A STEREOSELECTIVE APPROACH TO ALPHA-EPIMERIC BETA-ALKOXY-ALPHA-AMINO ACIDS

被引:0
|
作者
DONDONI, A [1 ]
JUNQUERA, F [1 ]
MERCHAN, FL [1 ]
MERINO, P [1 ]
TEJERO, T [1 ]
机构
[1] UNIV ZARAGOZA,CSIC,ICMA,DEPT QUIM ORGAN,E-50009 ZARAGOZA,SPAIN
来源
SYNTHESIS-STUTTGART | 1994年 / 12期
关键词
NITRONES; HYDROXYAMINES; 2-LITHIOFURAN; BETA-ALKOXY-ALPHA-AMINO ACIDS; ASYMMETRIC SYNTHESIS;
D O I
暂无
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
The addition of 2-lithiofuran (1) to the N-benzyl nitrones 2a-d, derived from chiral alpha-alkoxy aldehydes, affords beta-alkoxy-alpha-hydroxyamino-2-alkylfurans in good yields and with syn selectivity. Conversely, the reaction with the same nitrones precomplexed with diethylaluminum chloride leads to the same adducts but with anti selectivity. Three pairs of epimeric hydroxylamines are subjected to reductive N-dehydroxylation with titanium(III) chloride and then to furyl-carboxylic acid conversion with ruthenium tetroxide to give the corresponding alpha-epimeric beta-alkoxy-alpha-amino acids.
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页码:1450 / 1456
页数:7
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