A Chiral Ag-Based Catalyst for Practical, Efficient, and Highly Enantioselective Additions of Enolsilanes to α-Ketoesters
作者:Laura C. Akullian、Marc L. Snapper、Amir H. Hoveyda
DOI:10.1021/ja061166o
日期:2006.5.1
A Ag-based chiral catalyst promotes efficient and highlyenantioselective aldol additions of ketone-derived enolsilanes to alpha-ketoesters in the presence of a readily available amino acid-based ligand and commercially available AgF2. alpha-Ketoester substrates may bear alkyl, alkenyl, and aryl substituents; reactions proceed to >98% conversion to afford the desired tertiary alcohols in 61->98% isolated
在容易获得的基于氨基酸的配体和市售的 AgF2 存在下,基于 Ag 的手性催化剂促进了酮衍生的烯醇硅烷向 α-酮酯的高效和高度对映选择性羟醛加成。α-酮酯底物可带有烷基、烯基和芳基取代基;反应进行到 >98% 的转化率,以 61->98% 的分离产率和 60-96% 的 ee 得到所需的叔醇。与之前报道的方法相比,在空间要求严格的底物上观察到了最高的对映选择性,并且反应可以在未蒸馏的溶剂中、在空气中使用低至 1 mol% 的催化剂进行。
Highly Modular Synthesis ofC1-Symmetric Aminosulfoximines and Their Use as Ligands in Copper-Catalyzed Asymmetric Mukaiyama-Aldol Reactions
作者:Martin Langner、Pauline Rémy、Carsten Bolm
DOI:10.1002/chem.200500497
日期:2005.10.21
The development of C1-symmetricaminosulfoximines, their highly modular synthesis, and their application in enantioselective copper-catalyzed Mukaiyama-type aldolreactions between pyruvates and enolsilanes is described. In this context, the influence of the ligand architecture as well as the optimization of the reaction conditions are discussed. In detail, the dependence of the catalyst efficiency
A convenient enantioselective decarboxylative aldol reaction to access chiral α-hydroxy esters using β-keto acids
作者:Zhiqiang Duan、Jianlin Han、Ping Qian、Zirui Zhang、Yi Wang、Yi Pan
DOI:10.3762/bjoc.10.95
日期:——
We show a convenient decarboxylative aldol process using a scandium catalyst and a PYBOX ligand to generate a series of highly functionalized chiral alpha-hydroxy esters. The protocol tolerates a broad range of beta-keto acids with inactivated aromatic and aliphatic alpha-keto esters. The possible mechanism is rationalized.