Unprecedented Effects of Additives and Ligand-to-Metal Ratio on the Enantiofacial Selection of Copper-Catalyzed Alkynylation of α-Imino Ester with Arylacetylenes
作者:Zhihui Shao、Jun Wang、Kai Ding、Albert S. C. Chan
DOI:10.1002/adsc.200700237
日期:2007.10.8
The first catalytic asymmetric addition of arylacetylenes to α-iminoesters was carried out using chiral copper(I) complexes as catalysts under mild reaction conditions, providing the corresponding alkynylation products in good yields with 67–74 % ee values. Profound effects of the ligand-to-metalratio and additives on the stereofacial selection were observed. Both enantiomers of a given product can
reaction of ethyl glyoxylate, para-anisidine, and aliphatic, aromatic alkynes catalyzed by CuOTf·0.5C6H6/pybox 7 has been developed. The protocol provided the corresponding chiral β,γ-alkynyl α-amino acidderivatives in good yields and 66–74% ee.
已经开发了CuOTf·0.5C 6 H 6 / pybox 7催化的乙醛酸乙酯,对茴香胺和脂肪族,芳族炔烃的第一催化不对称三组分反应。该方案以高收率和66-74%ee提供了相应的手性β,γ-炔基α-氨基酸衍生物。
Copper-Catalyzed Aerobic Enantioselective Cross-Dehydrogenative Coupling of <i>N</i>-Aryl Glycine Esters with Terminal Alkynes
作者:Zhiyu Xie、Xigong Liu、Lei Liu
DOI:10.1021/acs.orglett.6b01328
日期:2016.6.17
A copper-catalyzed enantioselective cross-coupling of a Csp3–H moiety (N-aryl glycine ester) with a Csp–H component (terminal alkyne) using molecular oxygen as the terminal oxidant is described for the first time. The sustainable method provides an efficient and environmentally friendly approach to rapidly prepare a diverse array of optically active non-natural α-amino acids.
Copper(I)-catalyzed enantioselective alkynylation of α-imino esters: ligand-to-metal ratio effects and mechanistic studies
作者:Fangzhi Peng、Zhihui Shao、Albert S.C. Chan
DOI:10.1016/j.tetasy.2010.02.020
日期:2010.3
An unprecedented effect of the ligand-to-metal ratio on the stereofacial selection in the copper-catalyzed enantioselective addition of terminal alkynes to N-PMP-α-imino esters was observed. An excess of ligand was found not to be beneficial, on the contrary, an excess of copper was found to be beneficial. Moreover, both enantiomers of the alkynylation product were obtained with almost the same enantiomeric