关键词： 有机金属试剂   不对称合成   手性试剂   手性催化剂  

摘要： 本文综述了有机金属试剂在不对称有机合成中的应用。介绍了应用手性试剂进行不对称有机合成，以及应用手性催化剂进行不对称合成的方法。

关键词： 不对称合成   晶体结构   螺环化合物   氧氮杂草二酮  

摘要： 利用手性源（2R，3S）－3，4-二甲基-2-苯基-1，4-氧氮杂-5,7-二酮（1）合成了具有光学活性的7，8-二甲基-3，6-二苯基-5-氧-8-氮螺[2．6]壬-4，9-二酮（3）．测定了化合物（3）的晶体结构，并讨论了在环加成反应中的不对称诱导作用的机理．

关键词： Enolates   Carbene complexes   Adducts   Molecular structure   Aldol reactions  

摘要： Versatile, efficient reagents for asymmetric synthesis can be generated in one step from alkoxy or acetoxy Fischer carbene complexes and the commercial chiral auxiliary 1,5-dimethyl-4-phenyl-2-imid...

关键词： 哥纳香醇甲   抗肿瘤活性   不对称合成  

摘要： 哥纳香醇甲（１）是从番荔枝科哥纳香属植物海南哥纳香的根和茎皮中分离得到的有明显抗肿瘤活性的化合物，本文以αＤ葡庚糖酸内酯为原料，经９步反应对其进行了不对称合成研究，总收率为１３３％。根据药物设计原理，设计合成了２６个类似物，并进行了抗肿瘤活性筛选，初步结果表明大部分化合物体外对多种瘤株有不同程度的抑制作用。

关键词： 手性烷基α   糠胺   合成方法   天然产物   不对称合成  

摘要： 该论文的工作是先研究手性烷基α-糠胺的合成方法,然后利用它对非天然α-氨基酸、1-脱氧氮糖化合物、多取代哌啶类生物碱Desoxoprosphylline及1-Deoxycastanospermine进行了不对称合成研究.

关键词： isocarbacyclin   asymmetric olefination   allylic sulfoximine   cross-coupling reaction   chiral lithium amide  

摘要： An asymmetric synthesis of isocarbacyclin (2) was achieved from ketone 7 by the olefination-isomerization-coupling process with chiral sulfoximines. The vinylic sulfoximine 6 (greater than or equal to 98% de) was prepared from ketone 7 and lithiosulfoximine 8 by an asymmetric olefination via an addition-elimination process. Model experiments, aiming at a rationalization of the asymmetric induction in the elimination of hydroxysulfoximines, with ketone 12 and lithiosulfoximine ent-8 revealed formation of the silyl ether 15 as an intermediate which eliminated LiOSiMe3 upon reaction with nBuLi under formation of (S,Z)-alkene 17 (greater than or equal to 98% de). Reaction of the C,O-dilithiosulfoximine 19 with ClSiMe3 led to elimination of LiOSiMe3 and also gave 17 (greater than or equal to 98% de). Methylation of 19, however, furnished the corresponding alpha-methyl-substituted beta-hydroxysulfoximines, 20 and 21, in a ratio of 75:25. Isomerization of sulfoximine 6 gave the allylic sulfoximine 5 (96% de) whose absolute configuration was determined by X-ray structure analysis. Cross-coupling reaction of 5 with cuprate 23 delivered with high regioselectivity alkene 25. A similar reaction of 5 with the organocopper reagent 26, which was prepared from (benzyloxy)methylmagnesium chloride, in the presence of BF3. OEt2 and halide afforded alkene 27. Ketone 28 is a potential starting material for the asymmetric synthesis of 3-oxaisocarbacyclin. Besides alkenes 25 and 27 sulfinamide 24 (97% ee), whose conversion to 8 has been already described, was isolated in 90% yield. The key step in the sequence leading to the construction of the omega-side chain was the deprotonation of ketone 4b with a complex of lithium (R,R)-bis(alpha-phenylethyl)amide and Lithium chloride, ***, which gave enolate 3. The use of *** in deprotonation of 4b afforded the isomeric enolate 30. Enolates 3 and 30 were trapped as the silyl ethers 31 (90% ie) and 32 (92% ie), respectively. The aldol r

关键词： trifluoroacetaldehyde   derivatives   Alcohols   Optical activity   Asymmetric synthesis   Derivatives  

摘要： Reaction of trifluoroacetaldehyde with an alcohol in the presence of a catalytic amount of (R)-BINOL-Ti(O-i-Pr)(2) gives optically active 1-alkoxy-2,2,2-trifluoroethanol with high ee.

关键词： 1-Aminoallyl anions, chiral   Alkylation   Asymmetric synthesis   Homoenolate equivalents, chiral   β-Methyl ketones, chiral  

摘要： 3-Substituted aliphatic ketones 10 have been obtained in excellent optical yields by alkylation of the aminoallyllithium compound endo-8, a homoenolate equivalent of hexane-3-one, using prolinol ether (SMP) as the chiral auxiliary. The intermediate endo-8 was generated by tin-lithium exchange of the 3-stannylated enamine 7a with butyllithium. An improved hydrolysis procedure for the resulting enamines is described. Some mechanistic implications with respect to the formation as well as the alkylation of endo-8 are discussed.

关键词： Purification   Anions   Enantioselective synthesis   Organic compounds   Boron  

摘要： Highly stereoselective boronic ester chemistry has been used for the synthesis of (4S,6S,7S)-7-hydroxy-4,6-dimethylnonanone (1), the pheromone of the cigarette beetle. 2-Bromo-1-butene (8) was made from 1-butyne via bromoboration and protodeboronation, and was converted to 1-ethylethenylmagnesium bromide. (R,R)-1,2-Dicyclohexyl-1,2-ethanediol ["(R)-DICHED"] methylboronate was treated with (dichloromethyl)Lithium to yield (R)-DICHED (S)-1-chloroethylboronate (9), which with 1-ethylethenylmagnesium bromide yielded (R)-DICHED (R)-(2-ethyl-1-methyl-2-propenyl)boronate (10). Further chain extensions with (chloromethyl)lithium, (dichloromethyl)lithium followed by methylmagnesium bromide, and (dichloromethyl)lithium followed by ethylmagnesium bromide completed assembly of the carbon skeleton. Deboronation with hydrogen peroxide yielded (3S,5S,6S)-2-ethyl-3,5-dimethylocten-6-ol (14), which with osmium tetraoxide and sodium periodate yielded 1.

关键词： Alcohols   Nucleic acids   Monomers   Organic compounds   Acid and base chemistry