关键词： 粉蠹虫性信息素   不对称合成   6-甲基-5-庚烯-2-醇  

摘要： The S (+) sulcatol(1) was prepared in 4 steps. Sodium phenyl sulfinate was reacted with bromoacetone in ethanol to give 1 phenylsulfonyl 2 propanone(2). Alkylation of (2) by 1 chloro 3 methyl 2 butene(3) in the presence of K 2CO 3 through solid liquid PTC in DMF at 40～50 ℃ gave 3 phenylsulfonyl 6 methyl 5 heptene 2 one(4). The sulfone moiety of (4) was removed by Raney Ni reduction under mild conditions and the key intermediate prochiral 6 methyl 5 heptene 2 one(5) was obtained. Sulcatol(1) with optical purity of 94%e.e. was obtained by Baker′s yeast mediated reduction of (5).

关键词： L-肉碱   合成   维生素Bt   化学拆分法   不对称合成  

摘要： 对国内外化学合成L 肉碱的方法分三大类进行了综述 ,介绍了近 2 0种合成方法。参考文献 3 5篇。

关键词： 手性Schiff-碱   配合物   铜   不对称合成   希夫碱  

摘要： 利用合成的脱氢松香酸降解胺和工业生产的松香胺和水杨醛反应,制得手性Schiff碱,再与醋酸铜反应,合成得两种新型的手性Schiff碱—铜配合物,并对其进行了元素分析、红外光谱、紫外光谱表征。

关键词： 立体专一性   β-酮酸酯   酵母菌   还原   不对称合成  

摘要： 微生物可应用于不对称合成中 ,微生物法具有光学纯度高 ,环境污染少 ,成本低等优点 ,对一些具有生物活性的化合物的合成具有独到的作用。探讨了微生物中的酶在 β

关键词： 光学活性   拟除虫菊酯   二氯菊酸   不对称合成   差向异构   氯氰菊   光学异构体   杀虫剂   化学拆分   生物活性  

摘要： 1 研究光学活性拟除虫菊酯的意义 拟除虫菊酯是仿照天然除虫菊进行结构改造而获得的一类高效杀虫剂,全世界农用拟除虫菊酯产品的年销售额达14亿美元。进入70年代以来,农药研究已逐渐深入到分子立体异构领域,其中光学活性拟除虫菊酯的开发更是一马当先,至少已有近30个光学活性产品进入市场,而且这一领域的研究方兴未艾。 研究光学活性拟除虫菊酯,不仅可开发出生物活性更高的杀虫剂,而且在环境学、经济学、毒理学等方面都具有重要意义。 1.1 手性是一切生命的基础。

关键词： 螺-环丙烷   双内酯   合成   结构测定   不对称合成  

摘要： 描述了5-(l-孟氧基)-3-溴-2(5H)-呋喃酮新手性试剂1与氮亲核试剂发生的串联不对称双Michael加成/分子内亲核取代反应,一举生成4个新手性中心.报道了含有叔胺官能团的螺-环丙烷双内酯化合物4a～4d的合成方法以及结构测定.

关键词： 手性金属试剂   催化剂   不对称合成  

摘要： 研究报告了不同类型的不对称催化反应，介绍了它们在医药、农药、香精、食品添加剂等方面的实际应用。

关键词： Enantioselective total synthesis   Tandem conjugate addition   Stereoselective synthesis   (-)-hinokinin   Lactones   (-)-enterolactone   Alkylation   Iodine  

摘要： The oxidative homocouplings of lithium enolates of (4S)-3-(3-arylpropanoyl)-4-isopropyl-2-oxazolidinones and (4R,5S)-1-(3-arylpropanoyl)-3,4-dimethyl-5-phenyl-2-imidazolidinones gave the corresponding R,R-dimers stereoselectively with TiCl4, PhI(OAc)(2), or CuCl2 as an oxidant. The stereoselectivity can be explained by a radical coupling mechanism. Optically active dibenzylbutyrolactone lignans, such as (-)-hinokinin and (-)-dimethylmatairesinol, and dibenzylbutanediol lignans, such as (-)-dihydrocubebin and (-)-dimethylsecoisolariciresinol, were synthesized from the major R,R-dimers. The oxidative coupling of (4R,5S)-1-(3-arylpropanoyl)-3,4-dimethyl 2-imidazolidinones with LDA-I-2 gave R,S-dimers mainly, and this result can be explained by an S(N)2 mechanism.

关键词： Catalyzed carbonyl allylation   Altohyrtin-c spongistatin-2   Olive flypheromone   Homoallylic alcohols   Trimethylenemethane dianion   Enantioselective synthesis   Enantiomeric purities   Aldehydes   1   7-dioxaspiroundecane   Functionalization  

摘要： The double allylboration of aldehydes using 1,3-bis(diisopinocampheylboryl)-2-methylenepropanes(R,R)-3 and (S,S)-3 under Brown's salt-free conditions provides Ct-symmetric 3-methylenepentane-1,5-diols 1 in excellent enantiomeric excess. The absolute stereochemistry of the products was confirmed by a single-crystal X-ray study of bis-Mosher ester 6g. Desymmetrization and further functionalization of diol la were achieved by treatment of the bis-BOC carbonate 13 with IBr in toluene at -80 degrees C to give cyclic iodocarbonate 14 as a single diastereomer. This methodology is also applicable in natural product synthesis;enantiomerically pure spiroketals 1,7-dioxaspiro[5.5]-undecanes 18 and 25, the latter representing an expedient synthesis of the AB ring system of the spongistatins 20, were easily accessed from simple starting materials in excellent yields and selectivities.

关键词： CYCLIC compounds   ASYMMETRIC synthesis  

摘要： Asymmetric synthesis of a trichothecane analogue, 4-deoxyverrucarol (2), was carried out through two types of ring expansion reactions. First, synthesis of the racemate of 2 was investigated. Thus, 1-[1-(tert-butyldimethylsiloxy)-ethyl]-1-methoxycarbonyl-2-hexen-4-one (10), prepared by Diels-Alder reaction, was converted into the cyclopropylidene 15. The cyclobutanone (+/-)-18 was obtained from 15 via dihydroxylation, followed by successive treatments with SO2CI2 in the presence of imidazole and Florisil. After transformation of (+/-)-18 into the vinylcyclobutanol (+/-)-19, the second ring expansion reaction was performed with Pd(OAc)(2) to provide the cyclopentanone (+/-)-20. The product was converted into the racemate of 4-deoxyverrucarol (2) through the cyclohexenone (+/-)22, but the diastereoselectivity during the introduction of the double bond was unsatisfactory. The selectivity was improved in the case of the asymmetric synthesis. The optically active cyclobutanone (+/-)-18 was prepared via AD reaction of 15 with 73% ee. After the transformation of (+/-)-18 into the cyclohexanone (-)-30 through the palladium-mediated ring expansion reaction, (-)-30 was subjected to the diastereoselective deprotonation reaction using the chiral amide. The key synthetic intermediate (-)-25 of 4-deoxyverrucarol (2) was synthesized in an optically pure form by taking advantage of a kind of kinetic resolution that occurred during the deprotonation step.