首页> 外文学位 >Organolanthanide-catalyzed intramolecular carbon-nitrogen bond-forming reactions and its application to the asymmetric synthesis of naturally occurring alkaloids (+)-pyrrolidine 197B and (+)-xenovenine.
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Organolanthanide-catalyzed intramolecular carbon-nitrogen bond-forming reactions and its application to the asymmetric synthesis of naturally occurring alkaloids (+)-pyrrolidine 197B and (+)-xenovenine.

机译:有机锡催化的分子内碳氮键形成反应及其在不对称合成天然生物碱(+)-吡咯烷197B和(+)-xenovenine中的应用。

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摘要

We have discovered that organolanthanide complexes of the general type Cp2LnCH(TMS)2 (Cp = η5-Me5C5; Ln = La, Sm, Y, Lu; TMS = SiMe3) serve as effective precatalysts for the rapid, regioselective, and highly diastereoselective intramolecular hydroamination/cyclization (IHC) of aminoallenes having the general formula RCH=C=CH-(CH2) n-CHRNH2 to yield the corresponding heterocycles RCH= CHCHNHCH&parl0;R &parr0; - CH2n-1 CH2 (R = CH3, n-C3H 7, n-C5H11; R = H, CH3, n-C4H9, CH 2=CHCH2CH2). The mono- and disubstituted pyrrolidines and piperidines produced bear an α-alkene functionality available for further synthetic manipulations. Kinetic and mechanistic data parallel organolanthanide-mediated intramolecular aminoalkene and aminoalkyne hydroamination/cyclization. The reaction rate is zero-order in [aminoallene] and first-order in [catalyst] over three or more half-lives. The turnover-limiting step is proposed to be the intramolecular insertion of the proximal allenic C=C bond into the Ln-N followed by rapid protonolysis of the resulting Ln-C bond.; We accomplished the total asymmetric syntheses of the pyrrolidine alkaloid (+)-197B and pyrrolizidine alkaloid (+)-Xenovenine using the aforementioned precatalysts, and the novel organolanthanide complexes Me2SiCp(tBuN)LnN(TMS)2 (Cp = η5-Me5C5; Cp = η5-Me4C5; Ln = Sm, Y; TMS = Me3Si). The strategy involves enantioselective syntheses of the aminoallene, (5S,8S)-5-amino-trideca-8,9-diene, and the aminoallene-alkene, (5S)-5-amino-pentadeca-1,8,9-triene, which then undergo regio- and stereoselective cyclohydroamination reaction. The rate and selectivity of the insertion process is highly sensitive to the steric demands of the substrate.
机译:我们发现,一般类型Cp ' 2 LnCH(TMS) 2 (Cp ' = η 5 -Me 5 C 5 ; Ln = La,Sm,Y,Lu; TMS = SiMe 3 )可作为具有通式RCH = C = CH-(CH 2 n n 的氨基丙二烯的快速,区域选择性和高度非对映选择性分子内胺化/环化(IHC)的有效前催化剂sub> -CHR ' NH 2 产生相应的杂环 RCH = CH CHNHCH&parl0; R <?Eqn TeX style =” scriptscript“> <?Eqn TeX input =” sp prime“> <?Eqn TeX endstyle =” scriptscript“> &parr0; - CH 2 n-1 C H 2 (R = CH 3 n -C 3 H 7 n -C 5 H 11 ; R ' = H,CH 3 n -C 4 H 9 , CH 2 = CHCH 2 CH 2 )。产生的单和双取代的吡咯烷和哌啶具有可用于进一步合成操作的α-烯烃官能度。动力学和机理数据平行于有机镧系元素介导的分子内氨基烯和氨基炔加氢胺化/环化反应。在三个或更多的半衰期中,[氨基丙烯]的反应速率为零级,[催化剂]的反应速率为一级。限制周转的步骤是将近端的烯丙基C = C键分子内插入Ln-N,然后对所得的Ln-C键进行快速质子分解。我们使用上述预催化剂和新型有机镧系元素Me 2 SiCp '' t BuN)LnN(TMS) 2 (Cp ' 5 -Me 5 C 5 ; Cp '' 5 -Me 4 C 5 ; Ln = Sm,Y; TMS = Me 3 Si)。该策略涉及对氨基苯丙氨酸( 5S,8S )-5-氨基-trideca-8,9-diene和氨基苯丙烯-烯烃(5 S 的对映选择性合成)-5-氨基-pentadeca-1,8,9-三烯,然后进行区域和立体选择性环氢化胺化反应。插入过程的速率和选择性对基板的空间需求高度敏感。

著录项

  • 作者

    Arredondo, Victor Manuel.;

  • 作者单位

    Northwestern University.;

  • 授予单位 Northwestern University.;
  • 学科 Chemistry Organic.; Chemistry Biochemistry.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 146 p.
  • 总页数 146
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 有机化学;生物化学;
  • 关键词

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