关键词： BINAP   金属配合物   不对称合成   催化剂   烯烃   酮   亚胺   结构   不对称氢化   关环反应  

摘要： 综述了BINAP金属配合物催化剂在烯烃、酮、亚胺的不对称氢化以及在关环反应、C-C键形成反应等中的应用.

关键词： α-氨基膦酸   α-氨基膦酸酯   催化不对称合成   化学计量不对称合成   光学活性  

摘要： 综述了近年来光学活性 α-氨基膦酸及其酯的各种不对称合成方法 ,包括化学计量不对称合成和催化不对称合成。重点介绍了近年发展起来的催化不对称合成方法 ,并且对各种合成方法的优劣进行了评述。

关键词： (S)-异丝氨酸   不对称合成  

摘要： (S) -异丝氨酸是一种具有生物活性的 β-氨基酸和重要的医药中间体。本文重点介绍了以手性化合物为原料合成 ( S) -异丝氨酸的路线 ,并对 ( S) -异丝氨酸的不对称合成路线进行了系统阐述。

关键词： asymmetric   chiral imide   enantioselective   fatty acid   hydroxylation   oleic acid   oxazolidinone  

摘要： Highly selective asymmetric synthesis of 2-hydroxy fatty acid methyl esters has been accomplished through chiral imide enolates. Five chiral oleic acid imides were prepared by reaction of oleic acid with pivaloyl chloride followed by reaction with five different lithiated chiral oxazolidinones including (R)-(+)-4-benzyl-2-, (S)-(-)-4-benzyl-2-, (4R,5S)-(+)-4-methyl-5-phenyl-2-, (4S,5R) -(-)-4-methyl-5-phenyl-2-, and (R)(+)-4-isopropyl-2-oxazolidinones in 88-92% yields. The chiral imides were reacted with NaN(Mq(3)i)(2) at -78 degreesC to give enolates, which subsequently reacted with 2-(phenylsulfonyl)-3-phenyloxaziridine to give hydroxylated products in 78-83% yields. Methanolysis of the hydroxylated products with magnesium methoxide gave methyl 2-hydroxyoleate. Enantiomeric excesses tee) of the products were determined to be very high (98-99% eel by H-1 nuclear magnetic resonance study after esterification of the hydroxy group with (S)-(+)-O-acetylmandelic acid. Enantioselective hydroxylation of other fatty acids including elaidic, petroselinic, vaccenic, and linoleic was evaluated under the similar conditions using (4R,5S)-(+)-4-methyl-5-phenyl-2-oxazolidinone as a chiral auxiliary to give 98% ee values for all cases.

关键词： .optically active   salen   asymmetric synthesis   BINOL   privileged ligands  

摘要： Different types of chiral "privileged" ligands 1 and 2 in promoting enantioselective addition of allylating agents to aliphatic and aromatic aldehydes;are described. Here, a new concept in the asymmetric allylation reaction is presented. Redox [Cr(Salen)] mediated addition of allyl halides to carbonyl compounds is described, and mechanistic investigations are discussed. These results open access to the fascinating area of the catalytic redox processes mediated by metallo-Salen complexes.

关键词： Redox reactions   Alcohols   Enantioselective synthesis   Chemical structure   Metathesis  

摘要： [GRAPHICS] This first asymmetric synthesis of enantiopure desacetylumuravumbolide and umuravumbolide via asymmetric reduction, allylboration, and ring closing metathesis confirms their revised structures and configurations. A convenient procedure to upgrade the enantiopurity of alpha,beta -acetylenic alcohols is also described.

关键词： STEREOCHEMICAL ANALYSIS   Activation entropy   deceleration   Reagents   tethers  

摘要： [GRAPHICS] Kinetic measurements to determine effective molarities of intramolecular reactions using 2,4-pentanediol and related tethers showed that methyl groups on the tether accelerate the major diastereomeric process but decelerate the minor process. The efficient promotion of stereocontrol is suggested to be due to chiral perturbation of the reaction rate through the entropy term, The conformation of the encounter complex of the reagent and reactant moieties was deduced by stereochemical analysis of the intramolecular adducts.

关键词： 苯甲醛   氰化氢   不对称合成   醇腈酶   (R)-苯乙氰醇   催化合成   生物催化  

摘要： 研究了水 /有机溶剂双相中来源于杏仁的 (R) 醇腈酶催化苯甲醛与HCN不对称合成 (R) 苯乙氰醇 ,系统探讨了有机溶剂、水相与有机溶剂相体积比、水相pH值和反应温度对反应速度、转化率和产物光学纯度的影响 .结果表明 ,上述因素对醇腈酶促不对称合成 (R) 苯乙氰醇反应均有显著影响 .异丙醚为该反应最好的有机溶剂 ,水相与有机溶剂相体积比以 1/ 2为宜 ,适宜的 pH值为 3 4,最佳反应温度为 0～ 5℃ .在该优化反应条件下 ,反应转化率和产物的光学纯度均高达 99%以上 .

关键词： 不对称合成   多相催化   固相化   手性修饰   修饰型多相手性催化剂   应用  

摘要： 本文评述了修饰型多相手性催化剂在不对称合成中的应用。按照不同的制备方法及催化反应对一些多相催化体系进行了归类总结 ,包括过渡金属手性配合物的固相化、修饰型手性固体催化剂、手性分子筛及嵌入型粘土手性催化剂。对酒石酸及金鸡纳碱修饰型金属催化剂的反应机理也进行了探讨。

关键词： α-氨基酸   不对称合成   "同翻转关系"理论  

摘要： 研究了新型α-氨基酸的不对称合成体系中物质组分的变化以及反应温度的改变对反应效果的影响.基于这些研究工作,提出了适当的反应机理,并对反应条件作了初步的优化.