Biomimetic epoxidation in aqueous media catalyzed by cyclic dipeptides
摘要:
We have developed a practical epoxidation of electron-deficient enones in aqueous media using cyclic dipeptides as bioinspired green catalyst. Optimizing the reaction conditions in a triphasic system led to efficient conditions providing epoxides with good enantioselectivities. Depending on the catalyst substituent chirality, both enantiomers are obtained. The cyclic rigidity impacts significantly the enantioselectivity.
The chiral monoaza-15-crown-5 lariat ethers annellated to methyl-4,6-O-benzylidene-α-d-glucopyranoside-1 or mannopyranoside 2 have been applied as phase-transfercatalysts in the epoxidation of substituted chalcones and chalcone analogues with tert-butylhydroperoxide resulting in significant asymmetricinduction. It was found that the position of the substituents in the aromatic ring of the chalcone
Asymmetric Epoxidation of Enones Promoted by Dinuclear Magnesium Catalyst
作者:Joanna A. Jaszczewska‐Adamczak、Jacek Mlynarski
DOI:10.1002/adsc.202100482
日期:2021.9.7
still a challenging task. In this perspective, we present the application of chiral dinuclear magnesium complexes for asymmetricepoxidation of a broad range of electron-deficient enones. We demonstrate that the in situ generated magnesium-ProPhenol complex affords enantioenriched oxiranes in high yields and with excellent enantioselectivities (up to 99% ee). Our extensive study verifies the literature
With only water as solvent, poly-l-leucine serves as supramolecular catalyst for the epoxidation of α,β-unsaturated ketones.
只用水作为溶剂,聚-亮氨酸作为α,β-不饱和酮的环氧化反应的超分子催化剂。
Crown-ether-modified cyclic dipeptides as supramolecular chiral catalysts
作者:Christopher Bérubé、Normand Voyer
DOI:10.1080/10610278.2017.1392521
日期:2018.3.4
the objective to develop supramolecular catalysts for useful chemical transformations, we report here a rapid and efficient solid-phase synthesis of novel cyclic dipeptides (crown-CDPs) with a diversity of L-DOPA derived crown ether substituents and stereochemistry. We prepared and characterized 14 crown-CDPs and evaluated their efficiency as supramolecular epoxidation catalysts in a water/hexanes biphasic
Highly selective multifunctional nanohybrid catalysts for the one-pot synthesis of α,β-epoxy-chalcones
作者:Dana-Georgiana Crivoi、Anna M. Segarra、Francesc Medina
DOI:10.1016/j.jcat.2015.11.020
日期:2016.2
An efficient one-pot heterogeneous process for producing chiral alpha,beta-epoxy-chalcones from the corresponding aldehydes and ketones, has been described. The nanohybrid materials based on poly-L-leucine immobilised into rehydrated hydrotalcites did not require any pre-activation and were easily recovered and recycled for four consecutive runs without losing their catalytic efficiency in terms of conversion, total selectivity towards the corresponding epoxy-chalcones and excellent enantioselectivity. (C) 2015 Elsevier Inc. All rights reserved.