Synthesis and Preferred Conformations of All Regio- and Diastereoisomeric Methyl 2,3-Fluorohydroxyalkanoates
作者:Wibke S. Husstedt、Susanne Wiehle、Christian Stillig、Klaus Bergander、Stefan Grimme、Günter Haufe
DOI:10.1002/ejoc.201001224
日期:2011.1
Selective syntheses of enantiopure regio- and diastereomeric methyl 2,3-fluoro-hydroxyalkanoates via four different routes employing two types of fluorination reagents are reported. The anti- and syn-3-fluoro-2-hydroxyalkanoates 1 and 3 were prepared by treating the corresponding epoxides with Olah's reagent (Py·9HF). Cyclic sulfates prepared from the enantiomeric diols were ring-opened with TBAF to give the
Process for preparing 2-amino-1, 3-alkanediol or a derivative thereof, process for preparing optically active dihydrosphingosine derivatives and intermediates used in that process
申请人:Takasago International Corporation
公开号:EP0761642B1
公开(公告)日:2001-02-07
Process for preparing 2-amino-1,3-alkanediol or derivative thereof,
申请人:Takasago International Corporation
公开号:US05925792A1
公开(公告)日:1999-07-20
A process for preparing an optically active dihydrosphingosine derivative is disclosed, comprising reducing a (2R,3R)-2-amino-3-hydroxyalkanoic acid derivative represented by formula (III): ##STR1## wherein R.sup.3 represents a straight-chain alkyl group having 7 to 21 carbon atoms; and R.sup.4 represents an amino group protecting group, (e.g., (2R,3R)-2-benzylamino-3-hydroxyoctadecanoic acid) with sodium tetrahydroborate in the presence of an acid. The process makes it feasible to produce an optically active dihydrosphingosine at high optical purity and through a simple process that is safe and easy to industrialize.
Efficient synthesis of chiral α,β-epoxyesters via a cyclic sulfate intermediate
作者:Linli He、Hoe-Sup Byun、Robert Bittman
DOI:10.1016/s0040-4039(98)00190-7
日期:1998.4
An efficient synthesis of chiral α,β-epoxyester 1 from chiral 2,3-dihydroxyester 2 has been developed. Ester 2 is converted to the corresponding cyclic sulfate 3, which is opened with either LiBr in THF or Bu4NBr in acetone at rt to furnish 2-bromo-3-hydroxyester 4. Treatment of 4 with K2CO3 in methanol at low temperature gives α,β-epoxyester 1 in excellent overall yield and in the same ee as in the
手性α,β环氧酯的有效的合成1从手性2,3- dihydroxyester 2已经研制成功。将酯2转化为相应的环状硫酸盐3,将其在室温下用THF中的LiBr或在丙酮中的Bu 4 NBr打开,以提供2-溴-3-羟基酯4。在甲醇中在低温下用K 2 CO 3处理4,得到的α,β-环氧酯1的总收率极好,且ee与起始二醇相同。