关键词： ANTIMALARIAL  

摘要： The antimalarial agents febrifugine ((+)-1) and isofebrifugine ((+)-2) were asymmetrically synthesized from chiral piperidin-3-ol ((+)-4), which was prepared by the reductive dynamic optical resolution of the 3-piperidone derivatives ((+/-)-3) using baker's yeast.

关键词： asymmetric synthesis   Grignard reagents   oxidations  

摘要： A chiral Grignard reagent with the metal-bearing carbon atom as the sole stereogenic center has been generated by asymmetric synthesis in >90 % ee (see scheme). Such reagents allow the elucidation of the stereochemical course of subsequent reactions (such as the shown oxidation), which provides hints to the mechanism (electron transfer reactions or polar additions).

关键词： REDUCTION   ENANTIOMERS   EPOXIDES  

摘要： The asymmetric synthesis of (6S,8R)-, (6S,8S)-, (6R,8S)- and (6R,8R)-heptacosane-6,8-diols from (2S)-, (2R)-1-[(R)-p-tolylsulfinyl]-2-heptanols and 1-icosanal is described.

关键词： OLEFIN METATHESIS   ORGANIC-SYNTHESIS   AMINO-ACIDS   ORGANOMETALLIC REAGENTS   DERIVATIVES   ETHERS  

摘要： Ring closing metathesis reactions of the dienes 6 and 9 leads to the nitrogen heterocycles 7 and 10, respectively, one of which 10c was converted into (R)-(-)-coniine.

关键词： amino acids   asymmetric synthesis   Michael additions   nickel  

摘要： DBU-catalyzed Michael addition reactions were shown to occur at room temperature between a nickel(II) complex of the Schiff base of glycine 1 and (S)- or (R)-N-(E-enoyl)-4-phenyl-3-oxazolidin-2-ones (2, see scheme). This reaction, which has an almost completely stereoselective outcome, provides a practical and generalized approach to a family of glutamic/pyroglutamic acids. R = alkyl, aryl.

关键词： 硫醚化合物   甲硫醚   不对称氧化   中国医学科学院中国协和医科大学   不对称合成方法   手性亚砜  

摘要： 手性催化剂作用下的硫醚类化合物的不对称催化氧化，是合成手性亚砜类化合物的简便、有效的方法。本论文以对甲基苯甲硫醚和对硝基苯甲硫醚为底物，研究并比较了20种手性配体作用下，上述硫醚类化合物不对称催化氧化反应的对映选择性，采用的手性配体有：（2R，3R）-酒石酸甲酯，（2R，3R）-酒石酸乙酯，（2R，3R）-酒石酸异丙酯，（2R，3R）-酒石酸苄酯，（2R，3R）-N，N’-二苯基酒石酰胺，（2R，3R）-N，N’-二苄基酒石酰胺，（2R，3R）-N，N’-二间甲苯基酒石酰胺，（2R，3R）-N，N’-二对甲苯基酒石酰胺，R-（+）-联萘二酚，S-（-）-联萘二酚，R-（-）-6，6′-二溴-1，1′-联荼-2，2′-二酚，S-（+）-6，6′-二溴-1，1′-联萘-2，2′-二酚，R-（+）-联萘二胺，S-（-）-联萘二胺，R-（+）-2，2′-N，N′-二（甲基氨基）-1，1′-联萘，S-（-）-2，2′-N，N′-二（甲基氨基）-1，1′-联萘，R-（+）-2，2′-二（甲磺酰氨基）-1，1′-联荼，S-（-）-2，2′-二（甲磺酰氨基）-1，1′-联萘，R-（-）-2，2′-N，N′-二（邻羟基苯亚甲基氨基）-1，1′-联萘，S-（+）-2，2′-N，N′-二（邻羟基苯亚甲基氨基）-1，1，1′-联萘。 将上述手性配体与不同的有机金属化合物、氧化剂组合成多种不对称氧化体系对硫醚进行氧化，发现Ti（O-iPr）4-（2R，3R）-酒石酸异丙酯-H2O-TBHP-分子筛（氧化体系Ⅰ），Ti（O-iPr）4-[R-（+）-联萘二酚]-H2O-TBHP（Ⅱ），Ti（O-iPr）4-[S-（-）-联萘二酚]-H2O-TBHP（Ⅲ），Ti（O-iPr）4-[R-（-）-6，6′-二溴-1，1′-联萘-2，2′-二酚]-H2O-TBHP（Ⅳ），和Ti（O-iPr）4-[S-（+）-6，6′-二溴-1，1′-联萘-2，2′-二酚]-H2O-TBHP（Ⅴ）等体系对于对甲基苯甲硫醚的不对称催化氧化均有较好的对映选择性，在这些氧化体系的作用下，产物对甲基苯甲亚砜的e.e.值最高达到77％。其中Ti（O-iPr）4-（2R，3R）-酒石酸异丙酯-H2O-TBHP-分子筛（Ⅰ）体系还可用于对硝基苯甲硫醚的不对称催化氧化，产物对硝基苯甲亚砜的e.e.值可以达到61％。 将上述优选出的催化氧化体系用于手性亚砜类药物莫达非尼和奥美拉唑的不对称催化氧化合成之中，使用Ti（O-iPr）4-[S-（+）-6，6′-二溴-1，1′-联萘-2，2′-二酚]-H2O-TBHP（Ⅴ）体系氧化莫达非尼前体硫醚化合物为莫达非尼时的收率和e.e.值分别为80％和46％，但前述几种氧化体系用于奥美拉唑的不对称催化氧化合成时未得到理想的结果，其收率和e.e.值仅为35％和9.2％。 同时，还建立了一种与现有工业生产方法相比较，更为简单、有效的合成消旋奥美拉唑的新的氧化方法，收率稳定在82％-92％之间，有希望应用于奥美拉唑的工业化生产。 通过化学合成和拆分制备了二十种光活手性配体。其中合成消旋联萘二胺的方法是新建立的，与文献方法比较收率提高，操作简便，更适合于大量制备。

关键词： asymmetric synthesis   auto-catalysis   molecular recognition   surface chemistry   zinc  

摘要： Morphologically chiral crystals of sodium chlorate induce highly enantioselective synthesis. Thus the addition of diisopropylzinc to 2-(tert- butylethynyl)pyrimidine-5-carbaldehyde in the presence of d- and l-NaClO₃ gives the (S)- and (R)-alkanol, respectively, in high yields and with high ee values.

摘要： A second-generation asymmetric synthesis of the AB-ring system of phorbolwas investigated. This study has alleviatedthe problemsassociatedwith the first generation racemic synthesis of the AB-ring system. The key step inthe approach is an intramolecularanionic cyclization reaction, which effectivelyforrns the trans-5,7-fused AB-ring. Chiral auxiliaries and the asymmetric aldol reaction were utilized to furnish the appropriate stereochemistry. The formation of the [3.2.1] oxabicycle 63 was achieved using the Rh-catalyzed [4+3] cycloaddition reaction, which imparts high diastereoselectivity. A selective zinc reduction was performed to give 64 with the hydroxyl and methyl groups restored in a syn orientation to each other. Cleavage of the chiral auxiliaries provedtroublesome, however, under the Krapcho conditions, selective removal of R-pantolactonewas achieved. Further manipulations involving protections, reductions and cleavage reactions were investigated. The precursors en route to the AB-ring have been made and the conditions have been optimized.

关键词： β-内酰胺  

摘要： 介绍了不对称合成 β-内酰胺的研究进展 ,详细讨论了手性 β-内酰胺的合成方法。

关键词： ALLYLIC ALKYLATIONS  

摘要： Asymmetric Pd(0) catalyzed allylic amination followed by a Ru catalyzed RCM-ROM sequence converted an easily accessible racemic cyclopentenol 2 to the functionalized tetrahydropyridine 9 which can be used for the asymmetrical synthesis of indolizidine 13.