关键词： Acid  

摘要： Examines the asymmetric synthesis of orthogonally protected amino acid L-threo-beta-hydroxyasparagine. Use of Sharpless asymmetric aminohydroxylation (AA) reaction in the synthesis; Efficacy of cinnamate esters as substrates for the Sharpless AA reaction; Production of amino alcohol 4 by AA reaction on methyl 4-methoxycinnamate (3).

关键词： 抗生素类   抗肿瘤/化学合成   指示剂和试剂   内酯类/化学   大环内酯类  

摘要： [GRAPHICS] A concise, stereospecific synthesis of radicicol dimethyl ether is presented. The strategy relies on a convergent three-stage assembly of the 14-membered lactone which has, as a key transformation, a novel ring-forming metathesis reaction utilizing a vinyl epoxide.

关键词： S-萘普生   缩酮   不对称合成   重排   水解   药物  

摘要： 研究了以 6 甲氧基 2 丙酰基萘和 ( 2R ,3R) 酒石酸二甲酯为原料 ,用分子筛代替甲磺酸作催化剂合成了缩酮 2 乙基 2 ( 6 甲氧基 2 萘基 ) 1 ,3 二氧杂环戊烷 ( 4R ,5R ) 二羧酸二甲酯 ,此缩酮经过不对称溴化、水解、重排、脱溴反应后 ,得到了S -( +) 萘普生 ,总产率达 4 2 .5% .本合成路线具有反应条件温和 ,操作方便 ,三废少等优点 .

关键词： asymmetric synthesis   hydrazones   ferrocenyl ligands   asymmetric catalysis   allylic substitution  

摘要： An efficient and flexible asymmetric synthesis of planar chiral ferrocenyl ligands bearing a stereogenic centre at the beta -position to the metallocene backbone is described. A variety of donor groups can be independently introduced as electrophiles, thus allowing electronic and steric fine-tuning of the ligands, which were investigated in Pd-catalyzed enantioselective allylic substitutions. By employing a P,S ligand, the alkylation of the standard test system (+/-)-1,3-diphenyl-2-propenyl acetate using dimethyl malonate/BSA as the nucleoph- ile proceeded in a quantitative yield with an ee of 97%, which is the best value reported so far in this reaction for a P boolean ORS ligand.

关键词： acetonitrile   cycloaddition   solvent effects   TRANS   Acetonitriles   Diels-Alder Reaction   Cycloaddition Reaction   Acetals   Asymmetric synthesis   selectivity   Solvents  

摘要： The beneficial influence of cis-isopropylidene acetal tether control groups, to facilitate the asymmetric synthesis of substituted decalins by intramolecular Diels-Alder reactions, is described. Compared to trans-acetonides, these cases proceed under milder conditions to afford the cis-fused adducts from an endo transition state. An unusual acetonitrile solvent effect exerts a dramatic influence on the diastereoselectivity. This strategy leads to the chiral nonracemic bicyclo[4.4.0]decane core of diverse natural products.

关键词： 非甾体抗炎药   S-酮基布洛芬   不对称合成   拆分方法  

摘要： 本文介绍了用Sharpless环氧化、氢解 ;氢化α一芳基丙烯酸 ;1 ,2—芳基迁移和手性醇得到S—酮洛芬的不对称合成法以及通过 (± )酮洛芬得到 (S)— (+)

关键词： 不对称合成   1,1'-联萘酚   苯乙胺   手性诱导试剂  

摘要： Experimental results are reported for the CuCl2-mediated asymmetric oxidative coupling of 2-naphthols in the presence of [-]α-methylbenzylamine to optically active （S）-（-）-1,1-bi-2-naphthol. Under anhydrous conditions and with a 3∶1 molarity ratio of α-methylbenzylamine to 2-naphthol, a fair enantioselection has been observed（up to 80.6% ee）.

关键词： Completion   SUCLA2 gene   4-Thia-1-Azabicyclo(4.2.0)Octanes   Sch   diastereoselective synthesis   Cholesterol   Asymmetric synthesis  

摘要： A concise, four-step, asymmetric synthesis of a β-lactam-based cholesterolabsorption inhibitor, Sch 57939, was developed. The discovery of a one-step enantio- anddiastereoselective synthesis of a trans-β-lactam provided easy access to the desired three chiralcenters. A novel zinc phenoxide-promoted ehter synthesis was reported for the completion of the sidechain.

关键词： .radical cyclization   diastereoselective   silyl   methyl group   exo-dig   endo-trig   exo-trig   new developments   vinyl radical   Radical chemistry   BMDMS  

摘要： This article reviews our contribution in the field of radical synthetic chemistry, focusing on cascades relying on the use of propargylic BMDMS ethers and asymmetric synthesis using enantiopure vinylsulfoxides.

关键词： Diels-alder reactions   Catalysis   Diets Alder reaction   Dienophiles   Catalysis   endonuclease R   Cyclopentadienes   Diels-Alder Reaction   Lewis acids   Cycloaddition Reaction   samarium diiodide   Asymmetric synthesis   acrylamides  

摘要： Stereo differentiated asymmetric syntheses have been achieved by S-indoline derivations. Diels-Alder cycloadditions of S-indoline chiral acrylamides with cyclopentadiene proceed with high diastereofacial selectivity, giving either endo-R or endo-S products depending on Lewis acid and the structures of chiral dienophiles. Diastereo- and enantioselective pinacol coupling reactions of chiral alpha -ketoamides mediated by samarium diiodide afforded extremely high diastereoselectivities. Enantiopure (S,S)- or (R,R)-2,3-dialkyltartaric acid and derivatives can be synthesized for the first time depending on the structure of alpha -ketoamides.