关键词： Reagents   Group 14 compounds   Adducts   Aldehydes   Transition states  

摘要： Marshall discusses additions of chiral organotin compounds to chiral and achiral aldehydes leading to intermediates for polypropionate and carbohydrate synthesis.

关键词： ortho-quinodimethanes   lignans   Diels-Alder   asymmetric   mandelate  

摘要： The total asymmetric syntheses of (-)-isolariciresinol dimethyl ether (6) and(-)-deoxysikkimotoxin (7) have been carried out, in an attempt to exploit a synthetic strategy recently developed for the synthesis of (-)-deoxypodophyllotoxin (1, R(1) = -CH2-, Ar = 3,4,5-trimethoxyphenyl). In so doing, a generalized method for the synthesis of aryltetralin lignans has been developed that should be applicable to a variety of substitution patterns and stereochemistries. A one-pot, 100% regio-selective reduction-lactonization procedure has been developed for the conversion of the ester 18b to (-)-deoxysikkimotoxin, which gave 93% isolated yield in that step.

摘要： This thesis describes three new approaches to the asymmetric synthesis of chiral proline derivatives from (R) and (S)-tert-butyl-3-benzoyl-4-methylene-2-oxazolidin-5-one. In the first Chapter, some important aspects of proline derivatives, specially the strategies used for the synthesis of these compounds was presented. It was found that for the preparation of proline derivatives in high enantiomeric purity, starting materials with a chiral auxiliary have generally been employed. In Chapter Two, the Michael addition reactions of the pyrrolidine enamines (223- 225) to (S)-2-tert-butyl-3-benzoyl-4-methylene-oxazolidin-5-one (222) and its enantiomer, (R)-(222), to give Michael addition adducts of the type (226) was examined. The Michael addition reactions of the pyrrolidine enamines (223) and (225) to the chiral oxazolidinones (S)-(222) or (R)-(222) favours cis 2,4-disubstituted oxazolidinone adducts while trans 2,4-disubstituted oxazolidinone adducts were favoured from the addition reactions of enamine (224). The diastereomeric adducts from the addition of (223) to (222) were readily separated and were converted to (5R, 2S) and (5S,2R)-cis-5-iso-propylproline, efficiently in good overall yields and in high enantiomeric purities. The extension of this protocol to the synthesis of (2S, 3aS, 7aS)- perhydroindole carboxylic acid (3) suffered from poor overall stereochemical control and a mixture of two diastereoisomeric products reasulted. In Chapter Three, the synthesis of polyfunctionalized proline derivatives via the asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides derived from N-alkylidene or N-arylidene imino esters (201), with the chiral oxazolidinone (222) as a dipolarophile, have been presented. The cycloadducts were obtained with a high degree of regio- and diastereoselectivity that resulted from addition of the dipole to the exo-cyclic methylene group of the oxazolidinone (222) from the less hindered side of the oxazolidinone ring. Good endo-d

关键词： 不对称   开放实验室   有机合成反应   基金资助  

摘要： １９９６年不对称合成联合开放实验室科学基金资助的申请指南一、研究方向：本实验室的研究方向是研究有机合成反应中的立体控制合成，发展既能高产率，又能高光学纯度地制备的光学活性异构体的新方法，研究有机合成反应中不对称诱异、立体控制的内在规律性，寻求和发展立...

关键词： 合成技术   精细化学工业   不对称   手性中心   中国科学院上海有机化学研究所   上海有机化学研究所  

摘要： 不对称合成技术姜标（中国科学院上海有机化学研究所）当前国际化学工业的重点已开始从大品种的化学产品和高聚物逐渐向生产中小型的高精化学产品转移。后者包括医药、农用化学品、香精和特殊化学中间体。这些化学品往往具有复杂的化学结构和手性中心。手性是宇宙间普遍的...

关键词： 液晶   鐵電性   光活性層列C 相   自發極化   不對稱合成   共融混合物   顯示技術  

摘要： 铁电性液晶近来的发展相当活泼，逐渐受到化学界的注目；本文对其历史、原理、分子结构设计、物性、合成方法、实用性混合物的调制及应用面等做一综合性的介绍。

关键词： 氨基   羟基   苯基戊酸   不对称合成   吡咯烷生物碱  

摘要： 吡咯烷生物碱及相关化合物的不对称合成研究（Ⅰ）黄培强，阮源萍（厦门大学化学系，厦门，３６１００５）关键词Ｐｒｅｕｓｓｉｎ，４－氨基－３－羟基－５－苯基戊酸，不对称合成，酰胺－α－烷基化，１．５－二苄基－４－苄氧基－２－吡咯酮（＋）－ｐｒｅｕｓｓｉｎ１...

关键词： CONJUGATE ADDITION   HOMALINE   AZALACTAMS   LACTAMS   ACIDS  

摘要： Both enantiomers of (S)- and (R)-4-phenyl-1,5-diazacyclooctan-2-ones (7) were synthesized stereo-selectively with good optical purity by the asymmetric conjugate addition of pyrazolidine to optically active vinyl sulfoxides, t-butyl (E)-2-[(R)- and (S)-p-tolylsulfinyl]cinnamates, respectively. Starting from 7, a synthesis of optically active homaline was achieved.