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首页> 外文学位 >Site- and enantioselective carbon-carbon and carbon-boron bond forming reactions catalyzed by copper-, magnesium-, zinc-, or aluminum-based N-heterocyclic carbene complexes.
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Site- and enantioselective carbon-carbon and carbon-boron bond forming reactions catalyzed by copper-, magnesium-, zinc-, or aluminum-based N-heterocyclic carbene complexes.

机译：基于铜，镁，锌或铝的N-杂环卡宾配合物催化的位和对映选择性碳-碳和碳-硼键形成反应。

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摘要

Chapter 1. In this chapter, the ability of chiral bidentate N-heterocyclic carbenes (NHCs) to activate alkylmetal reagents directly in order to promote C--C bond forming reactions in the absence of a Cu salt is presented. Highly regio- and enantioselective Cu-free allylic alkylation reactions of di- and trisubstituted allylic substrates with organomagnesium, organozinc, and organoaluminum reagents are demonstrated. Chiral bidentate sulfonate-bearing NHC-Zn and NHC-Al complexes are isolated and fully characterized. Based on crystal structures of these catalytic complexes, mechanistic details regarding Cu-free allylic alkylations with alkylmetal reagents are proposed.*;Chapter 2. New methods for efficient and highly enantioselective Cu-catalyzed allylic alkylation reactions of a variety of trisubstituted allylic substrates with alkylmagnesium and alkyl-, aryl-, 2-furyl-, and 2-thiophenylaluminum reagents are presented. Transformations are promoted by a chiral NHC complex in the presence of commercially available, inexpensive and air stable CuCl 2•H2O. Enantiomerically enriched compounds containing difficult-to-access all-carbon quaternary stereogenic centers are obtained.*;Chapter 3. New methods for highly site- and enantioselective Cu-catalyzed allylic alkylation reactions of allylic phosphates with vinylaluminum reagents are presented. The requisite vinylaluminums are prepared by reaction of readily accessible terminal alkynes with DIBAL-H and used directly without further purification. Vinyl additions are promoted in the presence of a chiral bidentate sulfonate-based NHC complex and a Cu salt. The desired SN2' products are obtained in >98% E selectivities, >98% S N2' selectivities, >98% group selectivities (2% i-Bu addition) and high enantioselectivities. The enantioselective total synthesis of the natural product bakuchiol highlights the versatility of the one-pot hydroalumination/Cu-catalyzed enantioselective allylic vinylation process.*;Chapter 4. Efficient and highly site-selective Cu-catalyzed hydroboration reactions of disubstituted aryl olefins with bis(pinacolato)diboron (B2(pin)2) are presented. Transformations are promoted by an NHC-Cu complex in the presence of MeOH, affording only secondary beta-boronate isomers. A Cu-catalyzed method for the synthesis of enantiomerically enriched secondary alkylboronates promoted by chiral NHC complexes is disclosed.*;Chapter 5. A new method for efficient and site-selective tandem Cu-catalyzed copper-boron additions to terminal alkynes with B 2(pin)2 in the presence of an NHC-Cu complex is demonstrated. In a one-pot process, Cu-catalyzed hydroboration of alkynes provides vinylboronates in situ, which undergo a second site-selective hydroboration to afford vicinal diboronates. Highly Enantiomerically enriched diboronates obtained through Cu-catalyzed enantioselective dihydroboration in the presence of chiral bidentate sulfonate-based NHC-Cu complex are obtained. The control of site selectivity in the first-stage hydroboration of alkynes is critical for efficient and highly enantioselective reactions in the tandem dihydroboration. Functionalizations of the vicinal diboronates described herein underline the significance of the current method.*;*Please refer to dissertation for diagrams.
机译：第1章。在本章中，介绍了在没有铜盐的情况下手性双齿N-杂环卡宾（NHC）直接活化烷基金属试剂以促进C-C键形成反应的能力。证明了二和三取代的烯丙基底物与有机镁，有机锌和有机铝试剂的高度区域选择性和对映选择性的无铜烯丙基烷基化反应。分离并充分表征了带有手性双齿磺酸盐的NHC-Zn和NHC-Al复合物。基于这些催化络合物的晶体结构，提出了有关使用烷基金属试剂进行无铜烯丙基烷基化反应的机理的详细信息。*；第2章。用于各种三取代烯丙基底物与烷基镁的高效和高对映选择性的Cu催化烯丙基烷基化反应的新方法提出了烷基，芳基，2-呋喃基和2-硫代苯基铝试剂。在市售，廉价且空气稳定的CuCl 2•H2O的存在下，手性NHC配合物可促进转化。获得了对映异构体富集的化合物，该化合物包含难以接近的全碳四元立体构象中心。*；第3章。提出了烯丙基磷酸酯与乙烯基铝试剂进行高位点和对映选择性Cu催化烯丙基烷基化反应的新方法。所需的乙烯基铝是通过容易获得的末端炔与DIBAL-H反应制得的，无需进一步纯化即可直接使用。在基于手性双齿磺酸盐的NHC复合物和铜盐的存在下，乙烯基的添加得到促进。以> 98％E选择性，> 98％S N2'选择性，> 98％组选择性（<2％i-Bu添加）和高对映选择性获得所需的SN2'产品。天然产物爆裂酚的对映选择性全合成突出了一锅加氢铝化/ Cu催化的对映选择性烯丙基乙烯基化过程的多功能性。*；第4章。高效，高选择性Cu催化的二取代芳基烯烃与bis（介绍了频哪醇（dipinon）（B2（pin）2）。在MeOH存在下，NHC-Cu络合物可促进转化，仅提供仲β-硼酸酯异构体。公开了一种铜催化的方法，该方法用于合成由手性NHC配合物促进的对映异构体富集的仲烷基硼酸酯。*;第5章。一种新的方法，用于向位炔与B 2（在NHC-Cu络合物的存在下显示了pin）2。在一锅法中，炔烃的Cu催化加氢硼化可在原位提供乙烯基硼酸酯，然后对其进行第二次位点选择性氢硼化以提供邻位的二硼酸酯。获得在手性双齿磺酸盐基NHC-Cu配合物存在下通过Cu催化的对映选择性二氢硼化获得的高度对映体富集的二硼酸酯。炔烃第一阶段硼氢化反应中位点选择性的控制对于串联二氢硼化反应中高效且高度对映选择性的反应至关重要。本文所述的邻位二硼酸酯的功能化强调了当前方法的重要性。*； *请参阅论文以获取图表。

著录项

  • 作者

    Lee, Yunmi.;

  • 作者单位

    Boston College.;

  • 授予单位 Boston College.;
  • 学科 Chemistry Organic.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 583 p.
  • 总页数 583
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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