Asymmetric copper-catalyzed allylic alkylation between allyl bromides and alkyl Grignard reagents using a P-chiral monophosphorus ligand is described. A range of terminal olefins bearing tertiary or quaternary carbon centers were formed in good branched/linear selectivities and excellent enantioselectivities at copper loadings as low as 0.5 mol %.
A phosphite–phosphoroamidite and diphosphoroamidite ligand library was applied in the Cu-catalyzedallylicsubstitution of a range of cinnamyl-type substrates using several organometallic nucleophiles. Results indicated that selectivity depended strongly on the ligand parameters (position of the phosphoroamidite group at either C-5 or C-3 of the furanoside backbone, as well as the configuration of
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
Copper-Free Asymmetric Allylic Alkylation with Grignard Reagents
作者:Olivier Jackowski、Alexandre Alexakis
DOI:10.1002/anie.201000577
日期:2010.4.26
Open wide and say AAA: The copper‐free asymmetric allylicalkylation reaction of Grignardreagents, catalyzed by N‐heterocyclic carbenes, is reported for allyl bromide derivatives. This reaction offers good enantioselectivity and good to excellent γ regioselectivity, particularly for the formation of quaternary chiral centers (see scheme; Mes=mesityl).
张开嘴说AAA:据报道,N-杂环卡宾催化了格氏试剂的无铜不对称烯丙基烷基化反应,是烯丙基溴衍生物的反应。该反应提供了良好的对映选择性和良好的至优异的γ区域选择性,特别是对于形成四元手性中心(参见方案; Mes =甲磺酰基)。
Development of Biisoquinoline-Based Chiral Diaminocarbene Ligands: Enantioselective S<sub>N</sub>2‘ Allylic Alkylation Catalyzed by Copper−Carbene Complexes
作者:Hwimin Seo、Dimitri Hirsch-Weil、Khalil A. Abboud、Sukwon Hong
DOI:10.1021/jo702512z
日期:2008.3.1
Chiral biisoquinoline-based diaminocarbene ligands (BIQ) were designed to create a chiral environment extended toward the metal center, which was confirmed by an X-ray structure. The concise ligand synthesis is highlighted by a modified Bischler−Napieralski cyclization of bisamides prepared from readily available chiral phenethylamines, and allows easy variation of the stereodifferentiating groups
设计基于手性双异喹啉的二氨基碳烯配体(BIQ),以创建向金属中心延伸的手性环境,这通过X射线结构得以证实。简明的配体合成是由易得的手性苯乙胺制备的双酰胺的Bischler-Napieralski环的修饰Bischler-Napieralski环合突出显示的,并且可以轻松改变立体分化基团。环己基-BIQ-铜配合物是使用Grignard试剂进行对映选择性S N 2'烯丙基烷基化的有效催化剂,显示出S N 2'区域选择性高于5:1,对映选择性在68-77%ee范围内。