关键词： 手性相转移催化剂   去氢枞酸   三甲基   PTC   樟脑酸   不对称合成   不对称诱导   催化作用   离子对   无水乙醇   手性季铵盐   去溶剂  

摘要： 利用手性季铵盐作为相转移催化剂进行不对称合成 是七十年代刚刚发展起来的一种新的不对称合成方法。 本文旨在利用我国丰富的天然资源，探索合成新的季铵 盐类手性相转移催化剂，并对其结构进行表征，对其催 化作用和不对称诱导效应进行研究。 论文工作主要分以下几个方面： 1．利用我国资源丰富的松香，从中提取右旋去氢枞 酸为原料，经中和、酯化、氢化、溴代、季铵化等反应， 合成两种新型手性一元季铵盐相转移催化剂：（+）—β —去氢枞酸基乙基三甲基溴化铵（PTCⅠ）和（+）— 去氢枞基三甲基溴化铵（PTCⅡ）。 2．以樟脑酸为原料，经过中和、酯化、季铵化等 反应，合成了一种新的手性二元季铵盐：（+）—樟脑 酸—O，O'—二（乙基三甲基溴化铵）(PTCⅢ)。 3．对涉及的手性产物和中间体用1HNMR、IR、 MS.、UV、ElementalAnal.等进行了系统的分析表征。 4．用C—烷基化反应和N—烷基化反应检验所合 D 〕 山东师范大学硕士毕业论文 成的手性相转移催化剂的催化作用和不对称诱导效应。 PTC和 PTCHI均有一定的催化作用和不对称诱导效 应，但所应用＿的反应得到的光学产率和化学产率都比较 于。 5。应用“离子对翠取”机理，探讨了手性相转移 催化剂的催化作用和不对称诱导效应。

关键词： 手性磷化合物   辅助剂   不对称合成   立体选择性  

摘要： 综述了手性磷化合物作为辅助剂在不对称合成中的应用.

关键词： SAMP hydrazones   alpha-alkylation   hydrazone cleavage   ketone reduction   mono-protected cyclohexanediones   asymmetric synthesis  

摘要： Alkylation of 1,4-cyclohexanedione monoethylene acetal SAMP-hydrazone with various electrophiles (10 examples given) and subsequent cleavage of the hydrazones with saturated oxalic acid furnished highly enantiomerically enriched alpha-alkylated mono-protected 1,4-cyclohexanedione derivatives in high yields and enantiomeric excesses of ee = 28, 80-greater than or equal to 99%. Reduction of the ketones gave the corresponding alcohols in good yields with high enantiomeric excesses (ee = 80-greater than or equal to 98%) and cis/trans-ratios of usually 85:15. (C) 2000 Wiley-Liss, Inc.

关键词： cyclohexanedione   furane   fungicidal agent   gamma-lactones  

摘要： 3, 4-Disubstituted gamma -lactones 9 and 10 were stereoselectively synthesized from 3,4-unsaturated aliphatic alcohol. The synthetic methods of homoallylic alcohol were discussed. Asymmetric dihydroxylation of the double bond was performed by Sharpless' method with (DHQD)(2)PHAL or (DHQ)(2)PHAL. The stereo-chemistry of the product was assigned. The (3R,4R)- and (3S,4S)-compounds were obtained with high enantiomeric excess.

关键词： asymmetric synthesis   chiral auxiliaries   Michael additions   phosphonic acids   TADDOLs  

摘要： Asymmetric C-P bond formation through phospha-analogous Michael addition to nitroalkenes leads with high asymmetric induction to α-substituted β-nitrophosphonic acids [Eq.(1)], which constitute valuable bifunctional synthetic building blocks and direct precursors to β-aminophosphonic acids. The key to success is a P nucleophile based on an easily removable TADDOL auxiliary.

关键词： b-内酰胺   不对称合成   手性  

摘要： 介绍了不对称合成b -内酰胺的研究进展,详细讨论了手性b-内酰胺的合成方法.

关键词： THIOOXIME S-OXIDES   ANTIBACTERIAL AGENTS   AMINO-ACIDS   PHOSPHONOPEPTIDES   INHIBITORS   ALAPHOSPHIN   ANTIBODY   ANALOGS   POTENT  

摘要： Darzens-type reaction of chloromethyl phosphonate with (S)-(+)-N-sulfinimines gave (Ss, 2S, 3R)-diethyl 3-aryl-2-N-(p-toluenesulfinyl)aziridinyl-phosphonate (3) in good yields.

关键词： ANTIMALARIAL  

摘要： The antimalarial agents febrifugine ((+)-1) and isofebrifugine ((+)-2) were asymmetrically synthesized from chiral piperidin-3-ol ((+)-4), which was prepared by the reductive dynamic optical resolution of the 3-piperidone derivatives ((+/-)-3) using baker's yeast.

关键词： asymmetric synthesis   auto-catalysis   molecular recognition   surface chemistry   zinc  

摘要： Morphologically chiral crystals of sodium chlorate induce highly enantioselective synthesis. Thus the addition of diisopropylzinc to 2-(tert- butylethynyl)pyrimidine-5-carbaldehyde in the presence of d- and l-NaClO₃ gives the (S)- and (R)-alkanol, respectively, in high yields and with high ee values.

关键词： ALLYLIC ALKYLATIONS  

摘要： Asymmetric Pd(0) catalyzed allylic amination followed by a Ru catalyzed RCM-ROM sequence converted an easily accessible racemic cyclopentenol 2 to the functionalized tetrahydropyridine 9 which can be used for the asymmetrical synthesis of indolizidine 13.