Silylation-Based Kinetic Resolution of α-Hydroxy Lactones and Lactams
摘要:
A silylation-based kinetic resolution has been developed for alpha-hydroxy lactones and lactams employing the chiral isothiourea catalyst (-)-benzotetramisole and triphenylsilyl chloride as the silyl source. The system is more selective for lactones than lactams, and selectivity factors up to 100 can be achieved utilizing commercially available reagents.
A simple and efficient 1H NMR method for determining the absolute configuration of chiral α-hydroxy acid esters using a competing enantioselective conversion (CEC) strategy was developed. The α-hydroxy acid esters were acylated in the presence of Feng's chiral N,N′-dioxide–scandium(III) complex, and the faster reaction was identified when one enantiomer of the chiral α-hydroxy acid ester was treated
开发了一种简单有效的1 H NMR方法,使用竞争对映选择性转化(CEC)策略确定手性α-羟基酸酯的绝对构型。在Feng的手性N,N'-二氧化物-scan(III)配合物存在下使α-羟基酸酯酰化,当手性α-羟基酸酯的一种对映体用两种对映体进行处理时,可以识别出更快的反应。通过NMR分析反应混合物中的配体,无需进一步纯化。提供助记符以帮助分配基板的绝对配置。
Method for the microbiological isomerisation of alpha-hydroxy carboxylic acids
申请人:Gluck Silvia
公开号:US20060148051A1
公开(公告)日:2006-07-06
The present invention relates to a method for the microbiological isomerization of alpha-hydroxycarboxylic acids using an alpha-hydroxycarboxylic acid racemase, the enzymes used for this method and microorganisms which express a suitable racemase activity, a screening method for microorganisms with alpha-hydroxycarboxylic acid racemase activity, the nucleic acid sequences encoding this enzyme, expression vectors, recombinant microorganisms which express this racemase, and methods for the production or isolation of a protein with alpha-hydroxycarboxylic acid racemase activity.