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
Enantioselective Michael Addition to α,β-Unsaturated Aldehydes: Combinatorial Catalyst Preparation and Screening, Reaction Optimization, and Mechanistic Studies
作者:Ivana Fleischer、Andreas Pfaltz
DOI:10.1002/chem.200902449
日期:2010.1.4
Shortcut to chiral catalysts: An efficient combinatorial strategy based on back reaction screening by ESI‐MS allows rapid evaluation of organocatalysts for the asymmetric Michael addition to α,β‐unsaturated aldehydes (see scheme). An unexpected nonlinear effect has been observed in this reaction, resulting from a double nucleophilic–electrophilic activation mechanism involving two catalyst molecules
Highly enantioselective and recyclable organocatalytic Michael addition of malonates to α,β-unsaturated aldehydes in aqueous media
作者:Subrata K. Ghosh、Kritanjali Dhungana、Allan D. Headley、Bukuo Ni
DOI:10.1039/c2ob26248g
日期:——
in our lab, has been found to be very effective for the Michaeladdition reaction in aqueous solvents involving a wide range of α,β-unsaturated aldehydes and malonatederivatives. For the reactions studied, good to excellent yields (73%–96%) and high to excellent enantioselectivities (up to 97%) were obtained using this catalyst. In addition, the catalyst could be recycled up to four times with gradual
Exploration of Structural Frameworks for Reactive and Enantioselective Peptide Catalysts by Library Screenings
作者:Kengo Akagawa、Junichi Satou、Kazuaki Kudo
DOI:10.1021/acs.joc.6b01591
日期:2016.10.7
By screening large-scale N-terminal l-prolyl peptide libraries, we explored efficient catalysts for asymmetric Michael addition of a malonate to an enal. The catalytically active peptides obtained by the screening could be categorized into two groups based on the similarity of amino acid sequences. One group of the peptides selectively gave an S-product, whereas the other gave an R-product, despite
Hollow structural effect of microporous organocatalytic polymers with pyrrolidines: dramatic enhancement of catalytic performance
作者:Kyoungil Cho、Jin Yoo、Hyeong-Wan Noh、Sang Moon Lee、Hae Jin Kim、Yoon-Joo Ko、Hye-Young Jang、Seung Uk Son
DOI:10.1039/c7ta02404e
日期:——
Hollow and microporous organocatalytic polymers bearing pyrrolidines (H-MOP-P) were prepared by template synthesis and post-synthetic modification and showed enhanced performance, compared to nonhollow ones.