关键词： 不对称合成   Darzens反应   手性氯乙酸酯   甲氧苯基  

摘要： 利用（－）－氯乙酸薄荷酯（１）和（－）－氯乙酸冰片酯（２）与对－甲氧基苯甲醛（３）进行不对称Ｄａｒｚｅｎｓ反应，制得（－）－３－（４－甲氧基苯基）－环氧乙烷－２－羧酸薄荷酯（４）和（－）－３－（４－甲氧基苯基）－环氧乙烷－２－羧酸冰片酯（５），并利用＾１Ｈ－ＮＭＲ谱确定了它们顺反构型，推测了分离得到的ｃｉｓ－４ａ和ｃｉｓ－４ｂ中手性碳（Ｃ２，Ｃ３）的绝对构型。

关键词： 钛试剂   不对称合成   有机合成  

摘要： 人们近来在不对称合成时，非常注意钛试剂的应用，很多出色的工作都借助于它们来完成。本文主要介绍人们近来用钛试剂有效地进行不对称Ｄｉｅｌｓ－Ａｌｄｅｒ反应、不对称亲核加成、烯丙醇的不对称环氧化等工作中的应用。

关键词： 不对称性   手性   对映体   旋光性   化合物  

摘要： 不对称性(asymmetry)是自然界中广泛存在的一种现象。在宏观上,如果一个物体不存在任何对称因素,那么该物体就具有不对称性。其重要特征是该物体与它的镜象不能互相重叠。不对称物体的这种不可重叠性正如人的左右手关系一样,故又常称为手性(chirality)。自然界的这种不对称现象在化学和生命科学中有着广泛的应用。

关键词： 光催化   缬氨酸   复合物   半导体  

摘要： 本文研究了在甲醇和氨水的水溶液里，手性的（＋）－ｄｉｏｐ－Ｒｈ（Ⅰ）复合物（ｄｉｏｐ：２，３－邻－异亚丙基－２，３－二羟基－１，４－双（二苯膦基）丁烷）作为不对称催化剂，粉末半导体ＣｄＳ、ＴｉＯ＿２、Ｐｔ／ＣｄＳ和Ｐｔ／ＴｉＯ＿２为光催化剂，用５００ＷＸｅ灯光照１０ｈ，３－甲基－２－氧代丁酸光催化不对称合成Ｌ－α缬氨酸已经实现，光学纯度最高达６４％ｅ．ｅ．。

关键词： 手性配体   不对称合成   催化反应   对称轴   综述  

摘要： 按配位原子的数目进行分类，综述了近年来研究较多的具有Ｃ_２对称轴的手性配体及其相关的不对称催化反应，并对该类手性配体的设计做了分析和总结。参考文献７９篇。

关键词： 电化学   不对称合成   诱导作用   光学活性  

摘要： 综述了电化学不对称合成的研究概况，按照诱导手性方式的不同分六类加以介绍。参考文献５８篇。

摘要： A number of phosphine oxides were synthesized via different routes. Grignard displacement of menthyl phosphinates afforded different enantiopure monophosphine oxides. By coupling the monophosphine oxides, bisphosphine dioxides I were prepared. 1,2-Ethynediylbis(diphenylphosphine oxide) was reacted with anthracene and its derivatives to give Diels-Alder adducts ethenoanthracenes, and two of them were further reduced to ethanoanthracenes by magnesium in methanol. A new enantiopure bisphosphine ligand, anthraphos (II), was prepared. Dibenzobarrelene derivatives III form well defined crystalline complexes with triphenylphosphine oxide as well as with bisphosphine dioxides I. Irradiation of the complexes in the solid state led, via the di-$\pi$-methane rearrangement, to pairs of regioisomeric dibenzosemibullvalene photoproducts. The ratio in which these products are formed was found to vary markedly with the structure of the phosphine oxide. Low to moderate photoproduct enantioselectivities were observed in the complexes with enantiopure diphosphine dioxides. Five of the complexes studied had their crystal and molecular structures determined by X-ray crystallography. Correlations between the photochemical behavior of the complexes in the solid state and their crystal structures are discussed. The new host IV forms crystalline inclusion complexes with a wide variety of aliphatic solvent molecules. The molecular and crystal structures of these complexes were analyzed by X-ray crystallography. The crystal structures show that the complexes with ethanol, 1-propanol and 2-propanol have the chiral space group $P2\sb1$2$\sb1$2$\sb1,$ where the absolute configuration of IV was assigned. The inclusion complexes can undergo the di-$\pi$-methane rearrangement to result in dibenzosemibullvalene derivative product V in solution and the solid state. In the case of the complexes with ethanol, 1-propanol and 2-propanol, the solid state photoreaction gave product V in more than 90% e.e.;

摘要： The daphnanes, tigliane and ingenane families of diterpene esters are isolated from the Euphorbiaceae and the closely related Thymelaeceae plant families. Individual species of these families have long been noted for their diverse toxicological effects on animals and man, including the induction of inflammation to the skin, purgative action in man, and tumor promotion. They have also been used as fish poisons and as an ingredient of arrow poisons. With such diverse toxicological activities, it is not surprising that the plants of these families have been utilized as drugs in both traditional and alternative medicine as treatments for growths and tumors, migraine, parasitic infections, bacterial infections, skin conditions, purgatives and abortifacients. Resiniferatoxin (RTX) is a naturally occurring daphnane which was identified in the latex of three species of Euphorbia (E. resinifera, E. poissonii and E. unispina) on the basis of its extraordinary irritant activity. Unlike the structurally related tigliane phorbol esters, RTX functions as an ultrapotent analog of capsaicin, the major pungent constituent of red pepper and other plants of the genus Capsicum. In light of the current use of capsaicin in human therapy, the evaluation of RTX and its analogs for the desensitization of vanilloid pathways is of tremendous interest. The identification and possible cloning of the putative receptor subclasses and analysis of their individual structure activity requirements will have a major impact on the development of more selective agents with optimized spectra of actions in which undesired effects like pungency and hypothermia can be dissected by chemical modification. This paper describes the first asymmetric synthesis of the complete daphnane skeleton, a key intermediate in our proposed synthesis of resiniferatoxin. The general strategy employed in this approach involves the rapid and stereoselective construction of the daphnane BC-ring moiety in a facially selective oxi

摘要： This project describes the rational design, synthesis and screening of several phosphine liquids containing the dihydrobenzazaphosphole-borane moiety. During initial synthetic studies orr/zo-lithiation methodology in N,N,N'-benzyl-trisubstituted ethylenediamine type systems was examined. Once orr/io-lithiation methodology had been optimised, trapping the rr/zo-anion produced with a P(ni) electrophile and protecting the generated P(III) centre with borane was examined. Existing deboration methodology was applied to the compound produced to give a P(III) / nitrogen bidentate ligand. This liquid was applied to the Pd catalysed allylic alkylation reaction giving reasonable enantiocontrol. Examination of the reaction mechanism suggested that a synthetically simpler monodentate P(III) liquid may be of interest. Using previously described methodology an N-silyl dihydrobenzazaphosphole-borane complex was synthesised. Deboration of this compound gave an unusually effective liquid for the Pd catalysed allylic alkylation reaction giving very good enantiocontrol. Further studies into alternative syntheses of the dihydrobenzazaphosphole core led to the development of a halogen-lithium exchange reaction with wide applicability to synthesis of unsymmetrical diphosphine ligands. A C2 symmetric diphosphine-diborane complex was synthesised using this methodology and the use of its deborated relative in Rh(I) catalysed hydrogenation of an N-acyl-(a)-aminoacrylate, Rh(I) catalysed hydrosilylation of acetophenone derivatives, and a Pd catalysed asymmetric variant on the Heck reaction are examined. Possible future work using this methodology is described.

摘要： Amidocuprate(I) reagents {Li[Cu(NR(2))(2)]} and higher order cyanocuprates(I) {Li-2[Cu(CN)(NR(2))(2)]} have been developed as a new class of nitrogen nucleophiles. These reagents underwent regioselective 1,4-additions to alpha,beta:gamma,delta-dienoates, whereas NHR(2) gave a 1,6-addition product and the lithium reagent LiNR(2) afforded a mixture of 1,4- and 1,2-addition products. The amidocuprates(I) were added to chiral alpha,beta:gamma,delta-dienones having a 8-phenyl-p-menth-3-yl or a 10,2-bornanesultam chiral auxiliary in order to produce 1,4-adducts in good to high diastereoselectivity. The addition of Li[Cu{N(Bn)(TMS)}2] and Li-2[Cu(CN){N(Bn)(TMS)}(2)] to 8-phenyl-p-menth-3-yl 5-phenyl-2,4-pentadienoate or N-(5-phenyl-2,4-pentadienoyl)-10,2-bornanesultam produced an (R)-chirality at the beta-position. The 1,4-addition of Li-2[Cu(CN)(N(Bn)(TMS))(2)] to the bornanesultam, followed by trapping with acetaldehyde, gave the alpha-(1-hydroxyethyl)-beta amino derivative as a single isomer in good yield. This three-component coupling was used in an asymmetric synthesis of a beta-lactam.