An efficient method for the diastereoselective synthesis of α-fluoro-β-hydroxy esters based on the radical reduction of α-bromo-α-fluoro-β-hydroxy esters

被引：5

作者：

Mima, K ^{[1
]}

Ishihara, T ^{[1
]}

Kuwahata, S ^{[1
]}

Konno, T ^{[1
]}

Yamanaka, H ^{[1
]}

机构：

[1] Kyoto Inst Technol, Dept Chem & Mat Technol, Sakyo Ku, Kyoto 6068502, Japan

来源：

TETRAHEDRON | 2002年 / 58卷 / 12期

关键词：

alpha-fluoro-beta-hydroxy esters; radical reaction; reduction; diastereoselection; chelation control; solvent effect;

D O I：

10.1016/S0040-4020(02)00119-9

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

When alpha-bromo-alpha-fluoro-beta-hydroxy esters were allowed to react successively with trimethylaluminum in toluene at -15degreesC for 0.5 h and with tributyltin hydride in the presence of a catalytic amount of triethylborane at -15degreesC for 4 h, the corresponding threo-alpha-fluoro-beta-hydroxyalkanoates were obtained highly diastereoselectively in good yields. On the other hand, the alpha-bromo-beta-hydroxy esters having an aromatic substituent were subjected to the reaction with tris(trimethylsilyl)silane in the presence of a catalytic amount of triethylborane in THF at -78degreesC for 10 h to give the corresponding erythro-alpha-fluoro-beta-hydroxyalkanoates with high erythro-selectivity in good yields, but those carrying an aliphatic substituent being reduced in an almost nonstereoselective manner. (C) 2002 Elsevier Science Ltd. All rights reserved.

引用

页码：2369 / 2376

页数：8

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