关键词： azadirachtin   insect antifeedant   decalin   CBS asymmetric reduction   intramolecular Diels-Alder reaction  

摘要： A synthesis of the tetracyclic decalin part of azadirachtin in the naturally occurring form is described. The key reactions involve the Corey-Bakshi-Shibata (CBS) asymmetric reduction of the ketone, and an intramolecular Diels-Alder (IMDA) reaction.

关键词： Efficient formal synthesis   Stemodane diterpenes   End game   (+/-)-aphidicolin   Alcohols   (+)-aphidicolin   Alder   Hydroperoxide   Epoxidations   Conversion  

摘要： The 8-epiaphidicolane skeleton (3) was formed in one key reaction by highly diastereoselective tandem transannular Diels-Alder (TADA)-aldol reactions from the trans-trans-cis trienic macrocycle (4). The unnatural derivative (11R)-(-)-8-epi-11-hydroxyaphidicolin (2) was thus constructed, and an original solution to the C16 functionalization problem of many aphidicolin (1) syntheses is presented.

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： 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： 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： .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.