Ir‐catalyzed Asymmetric Hydrogenation of α‐Imino Esters with Chiral Ferrocenylphosphine‐Phosphoramidite Ligands
作者:Xin‐Hu Hu、Xiang‐Ping Hu
DOI:10.1002/adsc.201900888
日期:2019.11.5
An Ir‐catalyzed asymmetric hydrogenation of α‐imino esters with unsymmetrical hybrid chiral ferrocenylphosphine‐phosphoramidite ligands for the synthesis of optically active α‐aryl glycines has been described. The result indicated that the presence of the iodo‐substitutent at the 3/3’‐position of the binaphthyl unit of ligand could significantly improve the catalytic performance. This method features
Conjugated imines and iminium salts as versatile acceptors of nucleophiles
作者:Makoto Shimizu、Iwao Hachiya、Isao Mizota
DOI:10.1039/b814930e
日期:——
development of synthetic methodologies where nucleophilicaddition reactions to imino carbons are utilized in crucial steps. This article summarizes double nucleophilicaddition reactions with alpha,beta-unsaturated aldimines, addition reactions using alkynyl imines, "umpoled" reactions of alpha-imino esters, and the use of iminium salts as reactive electrophiles.
Novel, chiral Lewisbase organocatalysts, which displayed poor enantioselection in the hydrosilylation of N-aryl β-enamino esters, were found to be the catalysts of choice in the hydrosilylation of α-imino esters. In the presence of 10 mol-% of the best catalyst, various α-imino esters underwent enantioselectivehydrosilylation to provide a wide range of chiral α-amino esters with good yields (up to
Asymmetric Synthesis of α-Allyl-α-Aryl α-Amino Acids by Tandem Alkylation/π-Allylation of α-Iminoesters
作者:John M. Curto、Joshua S. Dickstein、Simon Berritt、Marisa C. Kozlowski
DOI:10.1021/ol500506t
日期:2014.4.4
The first asymmetric synthesis of α-allyl-α-aryl α-amino acids by means of a three-componentcoupling of α-iminoesters, Grignard reagents, and cinnamyl acetate is reported. Notably, the enolate from the tandem process provides a much higher level of reactivity and selectivity than the same enolate generated via direct deprotonation, presumably due to differences in the solvation/aggregation state.
reactivity of α-imino thioesters indicates that they are very reactive substrates for Umpolung N-alkylation. In fact, treatment of α-aldimino thioesters with dialkylzinc reagents in the presence of aldehydes or imines gives three-componentcoupling products in good yields.
α-亚氨基硫酯反应性的理论计算表明它们是 Umpolung N -烷基化反应活性很高的底物。事实上,在醛或亚胺存在下用二烷基锌试剂处理α-醛亚氨基硫酯可以以良好的收率得到三组分偶联产物。