关键词： 鱼腥藻毒素   不对称合成   曼尼希反应  

摘要： 报道(一)-AnTx-a关键中间体的四步合成新途径,设计一个新型(一)-AnTx-a类似物并以同法合成其中间体,本法是对以Mannich反应为基础的AnTX-a的合成策略的补充。

关键词： 基脲基   苄基膦酸酯   不对称   生物活性  

关键词： .phosphine ligands   PdCl   binaphthyl   Catalytic asymmetric   exo   norbornene   diphenylphosphino   asymmetric reactions   MOP   Synthesis of Optically   active alcohols   norbornanol  

摘要： Axially chiral monophosphines 1, (S)-2-(diphenylphosphino)-2'-methoxy-1,1'-binaphthyl (MOP, 1a) and its analogs substituted with isopropoxy (1b), benzyloxy (1c), and ethyl (1d) at 2' position, were prepared. Reaction of simple terminal alkenes 5 (RCH=CH2: R = n-C4H9, n-C6H13, n-C10H21, PhCH2CH2, cyclo-C6H11) with trichlorosilane at 40-degrees-C in the presence of 0.1 or 0.01 mol % of palladium catalyst prepared in situ from [PdCl(pi-C3H5)]2 and (S)-1a proceeded with unusual regioselectivity (up to 94%) and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes 6 together with a minor amount of 1-(trichlorosilyl)alkanes 6'. Oxidation of the carbon-silicon bond gave optically active alcohols 8 (RCH(OH)CH3), enantiomeric purity ranging between 94% and 97% ee. The high enantioselectivity was also observed in the enantioposition-selective hydrosilylation of norbornene (9) and related meso bicyclic olefins catalyzed by the MOP/palladium, which gave exo-2-norbornanol (11) and related alcohols with up to 96% ee.

关键词： .asymmetric synthesis   enantiomerically pure   keteniminium  

摘要： New strategies for the asymmetric vicinal acylation of olefins and the synthesis of enantiomerically pure amino acids are presented. Both use, as key step, a cycloaddition reaction involving a reagent easily prepared from chiral amides derived from pyrrolidines with C2 symmetry.

关键词： .enantiomeric   aldehyde   unsymmetrical   enzymatic hydrolysis   prochiral   overall yield   diester   racemate   ester-acid   practical asymmetric synthesis  

摘要： A practical, chemoenzymatic, four-step synthesis of the LTD4 antagonist MK-0679 is described. The key steps are enzymatic hydrolysis of the prochiral diester to the ester-acid in 99% enantiomeric excess followed by aluminum mediated amidation of the methyl ester to afford MK-0679 in high overall yield. This synthesis is superior to the synthesis the racemate MK-0571.

关键词： 不对称合成   不对称放大   有机合成  

摘要： 在不对称合成反应中,使用低光学纯度的手性源物质得到高光学纯度的产物的现象,称为不对称放大。本文以日本的小国和野依两教授的奠基性工作为中心,对于不对称放大的发现、特点和机理以及发展前景,作扼要的介绍。

关键词： 性信息素   槐尺蠖   不对称合成  

摘要： 本文以丙炔醇和正溴庚烷为起始原料经过炔烃偶联,格氏试剂偶联反应,用Sharpless不对称环氧化反应合成了槐尺蠖性信息素cis-3,4-环氧-(Z,Z)-6,9-十七碳二烯的两个光学异构体.

关键词： .Enantioselective hydrolysis   enantioselective synthesis   PLAP   optical purities   BLAP   homoallyl   using crude   aryloxycyclohexan   arylcyclohexan   GLAP   chicken liver acetone   powder CLAP  

摘要： Chiral trans-2-aryloxycyclohexan-1-ols, trans-2-alkoxy cyclohexan-1-ols, trans-2-arylcyclohexan-1-ols, homoallyl alcohols, 1-aryl-1-alkanols, 1,2-diphenylethane-1,2-diol are prepared in high optical purities via enantioselective hydrolysis of acetates of the corresponding racemic alcohols using crude enzymes such as pig liver acetone powder (PLAP), goat liver acetone powder (GLAP), chicken liver acetone powder (CLAP) and bovine liver acetone powder (BLAP).

关键词： 光学活性   α-氨基酸   手性催化剂  

摘要： 在固-液两相条件下,探讨甘氨酸乙酯薄荷酮希夫碱(Ⅰ)与丙烯腈在不同反应条件下的不对称Michael加成反应,合成了光学活性的丙烯腈薄荷酮希夫碱的衍生物(Ⅱ),经进一步水解得到相应的光学活性的α-谷氨酸盐酸盐(Ⅲ).光学纯度P_o为0.82%～40.7%.