Synthesis of Chiral Amino Alcohols Embodying the Bispidine Framework and Their Application as Ligands in Enantioselectively Catalyzed Additions to CO and CC Groups
course of enantioselective transformations, bispidine amino alcohols built up by these two routes were investigated as chiralligands in the enantioselectively catalyzed addition of diethylzinc to aldehydes and chalcone. In general, tridentate ligands containing one chiral amino alcohol fragment and a second amino substituent without a stereogenic center were more efficient than tetradentate ligands with
已经开发了两种普遍适用的合成包含双吡啶骨架的手性氨基醇的路线。在线性路线 A 中,双吡啶骨架是由手性伯胺通过中间体形成哌啶酮和双吡啶酮依次构建的。在收敛路线 B 中,首先形成非手性双吡啶,然后通过氮碱与手性亲电试剂的反应引入 N-取代基。为了确定双吡啶核心及其 N 取代基是否能影响对映选择性转化的空间过程,研究了通过这两种途径构建的双吡啶氨基醇作为手性配体在二乙基锌对醛和查耳酮的对映选择性催化加成中。一般来说,含有一个手性氨基醇片段和没有立体中心的第二个氨基取代基的三齿配体比具有两个氨基醇结构单元的四齿配体更有效。使用最好的配体,二乙基锌对芳香族和脂肪族醛的对映选择性加成以 83-98% ee 进行,二乙基锌向查耳酮的镍催化加成达到 85% ee。
Synthesis of (4S,5R)-(–)-4-methyl-5-phenyloxazolidine-2-selone: a chiral auxiliary reagent capable of detecting the enantiomers of (R,S)-lipoic acid by<sup>77</sup>Se nuclear magnetic resonance spectroscopy
作者:Louis A. Silks、Jie Pang、Jerome D. Odom、R. Bruce Dunlap
DOI:10.1039/p19910002495
日期:——
(4S,5R)-(-)-4-Methyl-5-phenyloxazolidine-2-selone was constructed in 5 steps on the 10-gram scale. Se-77 NMR spectroscropic studies revealed that this selone served as a remarkably sensitive chiral auxiliary agent which readily distinguished the selone-coupled (R,S)-lipoic acid (DELTA-delta 0.119 ppm), even though its chiral centre was separated by 8 bonds from the observed nucleus.
An Approach to Enantioselective 5-endo Halo-Lactonization Reactions
作者:Jean Marc Garnier、Sylvie Robin、Gérard Rousseau
DOI:10.1002/ejoc.200700041
日期:2007.7
Enantioselective lactonization of 4-substituted but-3-enoic acids using iodobis(N-methylephedrine) hexafluoroantimonate in dichloromethane at low temperatures is reported. The presence of bis(N-methylephedrine)silver(I) hexafluoroantimonate, derived from the excess amounts of N-methylephedrine and silver hexafluoroantimonate that were necessary for the generation of the iodo complex in the reaction
Nanomole-Scale Assignment of Configuration for Primary Amines Using a Kinetic Resolution Strategy
作者:Shawn M. Miller、Renzo A. Samame、Scott D. Rychnovsky
DOI:10.1021/ja310620c
日期:2012.12.19
The absolute configurations of primary amines were assigned using a kinetic resolution strategy with Mioskowski's enantioselective 1-(R,R) and 2-(S,S) acylating agents. A simple mnemonic was developed to determine the configuration. A pseudoenantiomeric pair of reagents, 1-(R,R) and 2-(S,S)-d(3), was prepared and used to assay primary amines on a micromolar scale. The ESI-MS readout of the resulting
Method of preparing optically active alcohols which consist
申请人:Duphar International Research B.V.
公开号:US05329023A1
公开(公告)日:1994-07-12
The invention relates to a method of preparing optically active alcohols which consist substantially (at least 75% e.e.) or entirely of one enantiomer of formula 4 ##STR1## wherein R and A are as defined therein. The method comprises, which maintaining enantiomeric excess, converting an optically active cyanohydrin of formula 1 ##STR2## into optically active protected cyanohydrin of formula 2 ##STR3## converting the protected cyanohydrin of formula 2 into an optically active compound of formula 3 ##STR4## removing the protecting group B.