Isothiourea-catalysed enantioselective Michael addition of N-heterocyclic pronucleophiles to α,β-unsaturated aryl esters
作者:Chang Shu、Honglei Liu、Alexandra M. Z. Slawin、Cameron Carpenter-Warren、Andrew D. Smith
DOI:10.1039/c9sc04303a
日期:——
The isothiourea-catalysed enantioselective Michaeladdition of 3-aryloxindole and 4-substituted-dihydropyrazol-3-one pronucleophiles to α,β-unsaturated p-nitrophenyl esters is reported. This process generates products containing two contiguous stereocentres, one quaternary, in good yields and excellent enantioselectivities (>30 examples, up to > 95 : 5 dr and 99 : 1 er). This protocol harnesses the
Asymmetric Sulfa-Michael Addition of α,β-Unsaturated Esters/Amides Using a Chiral N-Heterocyclic Carbene as a Noncovalent Organocatalyst
作者:Jiean Chen、Yong Huang、Pengfei Yuan、Sixuan Meng
DOI:10.1055/s-0035-1561843
日期:——
We report an asymmetric sulfa-Michael reaction of α,β-unsaturated amides and estersusing a chiral N-heterocyclic carbene as the HOMO-raising organocatalyst. We discovered an interesting correlation between 13C NMR shifts of substrates and ee of their products. More electron-deficient Michael acceptors afforded higher enantioselectivity.
我们报告了使用手性 N-杂环卡宾作为 HOMO 提升有机催化剂的 α,β-不饱和酰胺和酯的不对称磺胺-迈克尔反应。我们发现底物的 13C NMR 位移与其产物的 ee 之间存在有趣的相关性。更多缺电子迈克尔受体提供更高的对映选择性。
Aryloxide-Facilitated Catalyst Turnover in Enantioselective α,β-Unsaturated Acyl Ammonium Catalysis
作者:Anastassia Matviitsuk、Mark D. Greenhalgh、Diego-Javier Barrios Antúnez、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/anie.201706402
日期:2017.9.25
β-unsaturated p-nitrophenyl ester substrate to facilitate catalyst turnover. This method was used for the enantioselective isothiourea-catalyzed Michael addition of nitroalkanes to α,β-unsaturated p-nitrophenyl esters in generally good yield and with excellent enantioselectivity (27 examples, up to 79 % yield, 99:1 er). Mechanistic studies identified rapid and reversible catalyst acylation by the α,β-unsaturated
Cooperative Palladium/Isothiourea Catalyzed Enantioselective Formal (3+2) Cycloaddition of Vinylcyclopropanes and α,β‐Unsaturated Esters
作者:Jacqueline Bitai、Alastair J. Nimmo、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/anie.202202621
日期:2022.6.20
Cooperative palladium and isothiourea catalysis allows the formal (3+2) cycloaddition of vinylcyclopropanes and α,β-unsaturated esters to generate functionalized cyclopentanes via an α,β-unsaturatedacyl ammonium intermediate with the addition of LiCl crucial to obtain high product diastereo- and enantioselectivity.