关键词： 单分散   微米级   氯球   聚合苯乙烯   氯甲基化   不对称合成  

摘要： 综述了国内外近 2 0年来单分散。

关键词： 脂肪酶   光学活性化合物   拆分   催化   不对称合成   有机溶剂  

摘要： 本文介绍了脂肪酶在不对称合成中的应用现状及发展趋势 ,特别是脂肪酶在有机溶剂中的拆分反应 。

关键词： asymmetric amplification   asymmetric catalysis   asymmetric synthesis   chiral auxiliary   non-linear effects  

摘要： The fundamental principles of non-linear effects (NLE) are reviewed. Particular emphasis is placed on the case of asymmetric amplification since it allows one to perform useful chemistry with if non-enantiopure chiral auxiliary. A strong asymmetric depletion in a catalytic reaction may lead to an underestimation of the actual enantioselectivity of the fully resolved ligand. The study of NLE's is also prosing useful as a mechanistic tool in asymmetric catalysis. Similar concepts may be extended to chiral reagents or to kinetic resolution. 1. What is a Non-Linear Effect in Asymmetric Synthesis? 2. The Conditions for Observing a Non-Linear Effect in Enantioselective Catalysis 3. Some Simple Models of NLE in Enantioselective Catalysis 4. Comparison of the Sizes of Asymmetric Amplifications 5. Rates and Non-Linear Effects in Asymmetric Catalysis 6. Non-Linear Effects Involving Chiral Reagents 7. Mechanistic Applications of Non-linear Effects 8. Synthetic Applications 9. Concluding Remarks.

关键词： Redox reactions   Alcohols   Organic compounds   Metabolism   Ketones  

摘要： [GRAPHICS] Starting from 8-oxabicyclo[3.2.1]oct-6-en-3-one and racemic 2,2-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one the C1-C16 segment of the bryostatins has been synthesized in 30 steps and 9% overall yield (17 steps longest linear sequence), Fragment coupling by dithiane strategy and protecting group manipulations provided an advanced chemodifferentiated northern half segment.

关键词： Sulfur   imines   enolate   Mannich reaction   esters   Asymmetric synthesis   Acetamides  

摘要： [GRAPHICS] The reaction of an (S,S)-(+)-pseudoephedrine acetamide based enolate with several imines afforded smoothly and with full stereochemical control a series of beta -substituted alpha -methyl-beta -aminoamides that upon hydrolysis/esterification afforded the corresponding beta -aminoester derivatives in good yields and in almost enantiomerically pure form.

关键词： Peptides and proteins   Reaction products   Nitrogen compounds   Monomers   Enantioselective synthesis  

摘要： [GRAPHICS] On addition of Et2AlCN/i-PrOH, masked oxo sulfinimines give alpha -amino nitriles that afford oxo alpha -amino acids on hydrolysis. These amino acids cyclize and are reduced to cis proline and cis pipecolic acids derivatives in high ee and good yield. This new procedure avoids many of the limitations related to the preparation of oxo amino acids from proteinogenic amino acids.

关键词： 2001年度   诺贝尔化学奖   威廉·诺尔斯   不对称合成   中学   化学教学   教学参考  

关键词： C2轴手性化合物   双恶唑啉试剂   金属络合物   催化   不对称合成  

摘要： 概括了近年来C_2轴手性双噁唑啉试剂及其金属络合物的合成及在催化不对称合成应用上的研究进展。

关键词： 合成方法学   α-氨基酸   不对称合成   α,β-去氢氨基酸衍生物   氢化反应   甘氨酸类似物   亲电反应  

摘要： α-氨基酸的不对称合成是合成方法学中的重要组成部分 ,由此而发展出来的方法成为不对称合成领域中的典范 .本文着重从合成方法学角度出发 ,总结了α-氨基酸不对称合成的最新进展 .

关键词： ASYMMETRIC synthesis   LACTAMS   HETEROCYCLIC compounds  

摘要： The synthesis and utility of a novel class of [5,3,0]-bicyclic lactams are described. Produced by the cyclodehydration of (R)-phenylglycinol with omega -keto acids, lactams 4-6 were obtained as separable diastereomeric mixtures (similar to2:1) in low yields (similar to 40%). Higher chemical yield (up to 61%) was realized tia an alternate route involving ring closure metathesis of 2-allyl-N-acroyl oxazolidines, 8. Stereoselective reductions of the syn-bicyclic lactams, 4a and 5a, occurred with the use of alane or lithiumaluminum hydride, affording azepine alcohols, 11a and;15a, of the R configuration at the 2-position, in good to moderate yields (50-88%). High selectivity was also observed in the diisobutylaluminum hydride reduction of the epimeric anti lactams, 4b and 5b, affording azepine alcohols, 11b and 15b, of the S configuration at C-2. Hydrogenolytic cleavage of the N-benzyl moiety afforded chiral 2-substituted perhydroazepines, (R)- and (S)-12, in good yields and good enantiomeric excesses (84-94%).