The readily available (+)-N-Benzyl-(S)-mandelamide catalyzes the enantioselective addition of dimethylzinc to α-keto esters to give α-methyl-α-hydroxy esters containing stereogenic quaternary centers with moderate to good yields (56-87%). A good enantioselectivity of the reaction is obtained for aryl and heteroaryl keto esters. For these substrates ee values of 75-90% are obtained. The enantioselectivity
容易获得的 (+)-N-苄基-(S)-扁桃酰胺催化二甲基锌与 α-酮酯的对映选择性加成,得到含有立体季铵中心的 α-甲基-α-羟基酯,产率适中至高 (56-87 %)。对于芳基和杂芳基酮酯,反应具有良好的对映选择性。对于这些基材,获得了 75-90% 的 ee 值。对于带有脂肪链的底物,对映选择性稍低。
Catalytic Asymmetric Addition of Dimethylzinc to α-Ketoesters, Using Mandelamides as Ligands
作者:Gonzalo Blay、Isabel Fernández、Alícia Marco-Aleixandre、José R. Pedro
DOI:10.1021/ol052997m
日期:2006.3.1
A strategy based on the control of the electron-donating capabilities of the coordinating groups of the ligand has been applied in the catalytic asymmetric addition of organometallic reagents to ketoesters. Mandelamides having deprotonated alcohol and carboxyamido groups catalyzed the addition of dimethylzinc to alpha-ketoesters with good yields and ee (up to 90%).
Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to Glyoxylates: Access to Optically Active Substituted Mandelic Acid Esters
作者:Diao Chen、Jian-Guo Liu、Xu Zhang、Ming-Hua Xu
DOI:10.1055/s-0037-1610722
日期:2019.9
A rhodium-catalyzed enantioselective addition of glyoxylates to arylboronic acids promoted by a simple chiral sulfinamide-based olefin ligand under mild reaction conditions is described. The reaction provides access to a variety of opticallyactive substituted mandelic acid esters in good yields with up to 83% ee. The catalytic system is also applicable to pyruvate addition. The synthetic utility of