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
Asymmetric Michael addition of malonates to various α,β-unsaturated aldehydes using an organocatalyst derived from trans-4-hydroxyproline in MeOH proceeds smoothly to afford the corresponding Michael adducts in high yields with high to excellent enantioselectivities.
Enantioselective organocatalytic Michael addition of malonates to α,β-unsaturated aldehydes in water
作者:Anqi Ma、Shaolin Zhu、Dawei Ma
DOI:10.1016/j.tetlet.2008.03.051
日期:2008.5
The Michaeladdition of malonates to α,β-unsaturated aldehydes catalyzed by O-TMS protected diphenylprolinols and acetic acid in water occurs at 0 °C to rt. In most cases, the reaction runs to completion in less than 24 h. A wide range of aldehydes including β-aryl, β-alkyl and β-alkenyl acroleins are found to be compatible with these conditions, providing the corresponding adducts in good yields and