Highly Homogeneous Stereocontrolled Construction of Quaternary Hydroxyesters by Addition of Dimethylzinc to α-Ketoesters Promoted by Chiral Perhydrobenzoxazines and B(OEt)3
作者:Rebeca Infante、Javier Nieto、Celia Andrés
DOI:10.1002/chem.201102913
日期:2012.4.2
A highly efficient enantioselective addition of Me2Zn to α‐ketoesters, assisted by a chiral perhydro‐1,3‐benzoxazine ligand, is described. This novel catalytic system offers homogeneous elevated enantioselectivities in the preparation of α‐hydroxyesters that bear a quaternary stereocenter, with a minor dependence on electronic and steric effects when aromatic, heteroaromatic, or aliphatic α‐ketoesters
描述了在手性过氢-1,3-苯并恶嗪配体的协助下,高效地将Me 2 Zn对映体选择性地添加到α-酮酸酯中。这种新型的催化体系在制备具有季立体中心的α-羟基酯时,提供了均相的提高的对映选择性,当使用芳族,杂芳族或脂族α-酮酯时,对电子和空间效应的依赖性较小。催化剂可被回收和再利用而不会损失活性。