Cu-Catalyzed Asymmetric Allylic Alkylations of Aromatic and Aliphatic Phosphates with Alkylzinc Reagents. An Effective Method for Enantioselective Synthesis of Tertiary and Quaternary Carbons
作者:Monica A. Kacprzynski、Amir H. Hoveyda
DOI:10.1021/ja0478779
日期:2004.9.1
Efficient enantioselective Cu-catalyzed allylicalkylations of aromatic and aliphatic allylic phosphates bearing di- and trisubstituted olefins are disclosed. Enantioselective C-C bond forming reactions are promoted in the presence of 10 mol % readily available chiral amino acid-based ligand (5 steps, 40% overall yield synthesis) and 5 mol % (CuOTf)2 x C6H6. Reactions deliver tertiary and quaternary stereogenic
公开了带有二和三取代烯烃的芳族和脂族烯丙基磷酸酯的有效对映选择性Cu催化的烯丙基烷基化。在 10 mol% 容易获得的手性氨基酸基配体(5 步,40% 总产率合成)和 5 mol% (CuOTf)2 x C6H6 存在下,对映选择性 CC 键形成反应得到促进。反应区域选择性地以 78-96% ee 传递叔和四元立体碳中心。提供了有关配体结构变化对烷基化过程的效率和对映选择性的影响的数据,以及机械工作模型。建议的模型涉及手性 Cu 络合物的双重作用:Cu(I) 中心与烯烃的结合是通过配体羰基之间的两点结合来促进的
A Readily Available Chiral Ag-Based N-Heterocyclic Carbene Complex for Use in Efficient and Highly Enantioselective Ru-Catalyzed Olefin Metathesis and Cu-Catalyzed Allylic Alkylation Reactions
作者:Joshua J. Van Veldhuizen、John E. Campbell、Russell E. Giudici、Amir H. Hoveyda
DOI:10.1021/ja050179j
日期:2005.5.1
ligand does not require optically pure biaryl amino alcohols, its synthesis is significantly shorter and simpler than the related first generation ligands bearing a chiral binaphthyl-based amino alcohol. The chiral NHC ligand can be used in the preparation of highly effective Ru- and Cu-based complexes (prepared and used in situ from the Ag(I) carbene) that promote enantioselective olefin metathesis and
Bidentate NHC-Based Chiral Ligands for Efficient Cu-Catalyzed Enantioselective Allylic Alkylations: Structure and Activity of an Air-Stable Chiral Cu Complex
作者:Andrew O. Larsen、Wenhao Leu、Christina Nieto Oberhuber、John E. Campbell、Amir H. Hoveyda
DOI:10.1021/ja046245j
日期:2004.9.1
Cu-catalyzed addition of alkylzincreagents to a range of allylic phosphates is promoted efficiently and with high enantioselectivity to afford tertiary as well as quaternarycarbon centers (up to 98% ee). Reactions proceed to completion with 0.5-5 mol % catalyst loading and are best promoted by commercially available CuCl2.2H2O. The X-ray structure of the chiral NHC-Ag(I) complex used in the study
Cu催化的烷基锌试剂向一系列烯丙基磷酸酯的加成得到有效促进,并具有高对映选择性,以提供叔和季碳中心(高达 98% ee)。反应在 0.5-5 mol% 的催化剂负载下进行到完成,最好由市售的 CuCl2.2H2O 促进。还报告了研究中使用的手性 NHC-Ag(I) 配合物以及具有催化活性的 NHC-Cu(II) 配合物的 X 射线结构;两种复合物都是空气稳定的,并且以 >/=95% 的分离产率形成。可在空气中处理的分离出的 Cu 络合物具有催化活性。本报告为使用手性 NHC 配体进行有效的铜催化烯丙基烷基化提供了第一个先例。