Recyclable Polyurea-Microencapsulated Pd(0) Nanoparticles: An Efficient Catalyst for Hydrogenolysis of Epoxides
摘要:
Pd nanoparticles (similar to2 nm in size) microencapsulated in polyurea is an efficient and recyclable catalyst for reductive ring-opening hydrogenolysis of epoxides, using either HCOOH/Et3N or H-2 as a hydrogen donor.
4-Substituted-α,α-diaryl-prolinols Improve the Enantioselective Catalytic Epoxidation of α,β-Enones
作者:Yawen Li、Xinyuan Liu、Yingquan Yang、Gang Zhao
DOI:10.1021/jo0617619
日期:2007.1.1
To seek novel metal-free organic catalysts for epoxidation with high stereoselectivity, a series of 4-substituted-α,α-diaryl-prolinols were synthesized in four steps from trans-4-hydroxyl-l-proline. These prolinol derivatives catalyzed the asymmetric epoxidation of α,β-enones to give the corresponding chiral epoxides in good yields and high enantioselectivities under mild reaction conditions. Studies
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
Bis(3,5-dimethylphenyl)-(S)-pyrrolidin-2-ylmethanol: an Improved Organocatalyst for the Asymmetric Epoxidation of α,β-Enones
作者:Alessandra Lattanzi
DOI:10.1002/adsc.200505370
日期:2006.2
The asymmetricepoxidation of α,β-enones by the readily available bis(3,5-dimethylphenyl)-(S)-pyrrolidin-2-ylmethanol and tert-butyl hydroperoxide (TBHP) is described. Stereoelectronic substitution on the aryl moiety of diaryl-2-pyrrolidinemethanols was found to significantly affect the efficiency with respect to the previously reported (S)-diphenyl-2-pyrrolidinemethanol. Improved reactivity and enantioselectivity
Asymmetric Oxidations
of Electron-Poor Alkenes Promoted by the β-Amino Alcohol/TBHP
System
作者:Alessandra Lattanzi、Alessio Russo
DOI:10.1055/s-0029-1216638
日期:——
the enantioselective organocatalyzed oxidation of electron-poor alkenes. Readily or commercially available β-amino alcohols displayed catalytic activity in the asymmetric epoxidation of α,β-enones and β-peroxidation of nitroalkenes with tert-butyl hydroperoxide (TBHP) as the oxidant. The corresponding epoxides and peroxides were isolated in good to high yield and enantioselectivity. α,β-enones - epoxides
The catalytic asymmetric epoxidation of enones using the La-BINOL-Ph(3)As=O complex generated from La(O-i-Pr)(3), BINOL, and Ph(3)As=O in a ratio of 1:1:1 is described herein. Using 1-5 mol % of the asymmetriccatalyst, a variety of enones, including a dienone and a cis-enone, were found to be epoxidized in a reasonable reaction time, providing the corresponding epoxy ketones in up to 99% yield and