Polystyrene-Supported Diarylprolinol Ethers as Highly Efficient Organocatalysts for Michael-Type Reactions
作者:Esther Alza、Sonia Sayalero、Pinar Kasaplar、Diana Almaşi、Miquel A. Pericàs
DOI:10.1002/chem.201101730
日期:2011.10.4
addition of aldehydes to nitroolefins and of malonates or nitromethane to α,β‐unsaturated aldehydes. The combination of the catalytic unit, the triazole linker, and the polymeric matrix provides unprecedented substrate selectivity, in favor of linear, short‐chain aldehydes, when the organocatalyzed reaction proceeds by an enamine mechanism. High versatility is noted in reactions that proceed via an iminium
Highly Active Water-Soluble and Recyclable Organocatalyst for the Asymmetric 1,4-Conjugate Addition of Nitroalkanes to α,β-Unsaturated Aldehydes
作者:Subrata K. Ghosh、Zilong Zheng、Bukuo Ni
DOI:10.1002/adsc.201000344
日期:2010.10.4
A novel strategy for the catalyticasymmetric conjugate addition of nitroalkanes to α,β-unsaturatedaldehydes in aqueous media has been developed by using diarylprolinol silyl ether in combination with benzoic acid as a water-soluble organocatalyst providing the desired adducts in good to excellent enantioselectivities (up to 95% ee). This catalyst can be recycled at least five times with only a slight
Efficient, Enantioselective Iminium Catalysis with an Immobilized, Recyclable Diarylprolinol Silyl Ether Catalyst
作者:Ina Mager、Kirsten Zeitler
DOI:10.1021/ol100166z
日期:2010.4.2
A highlyefficient approach for the synthesis, application, and recycling of immobilized diarylprolinol silyl ethers was developed. The MeOPEG-supported Jørgensen−Hayashi catalyst provides unchanged reactivity and selectivity as compared to the homogeneous catalyst, as demonstrated for the Michaeladdition of nitromethane to α,β-unsaturated aldehydes via iminium activation. In addition, the immobilization
Stereochemical Control of Enzymatic Carbon-Carbon Bond-Forming Michael-Type Additions by “Substrate Engineering”
作者:Yufeng Miao、Pieter G. Tepper、Edzard M. Geertsema、Gerrit J. Poelarends
DOI:10.1002/ejoc.201601126
日期:2016.11
of acetaldehyde to β‐nitrostyrene derivatives to yield chiral γ‐nitroaldehydes, which are important precursors for pharmaceutically active γ‐aminobutyric acids. In this study, we investigated the effect of different substituents at the aromatic ring of the Michael acceptor on the catalytic efficiency and stereoselectivity of the 4‐OT‐catalyzed acetaldehyde addition reactions. Highly enantioenriched (R)‐
Reactivity and Selectivity of Iminium Organocatalysis Improved by a Protein Host
作者:Alexander R. Nödling、Katarzyna Świderek、Raquel Castillo、Jonathan W. Hall、Antonio Angelastro、Louis C. Morrill、Yi Jin、Yu-Hsuan Tsai、Vicent Moliner、Louis Y. P. Luk
DOI:10.1002/anie.201806850
日期:2018.9.17
There has been growing interest in performing organocatalysis within a supramolecular system as a means of controlling reaction reactivity and stereoselectivity. Here, a protein is used as a host for iminium catalysis. A pyrrolidine moiety is covalently linked to biotin and introduced to the proteinhost streptavidin for organocatalytic activity. Whereas in traditional systems stereoselectivity is