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
<i>O</i>-TMS-α,α-diphenyl-(<i>S</i>)-prolinol Modified with an Ionic Liquid Moiety: A Recoverable Organocatalyst for the Asymmetric Michael Reaction between α,β-Enals and Dialkyl Malonates
作者:Oleg V. Maltsev、Alexandr S. Kucherenko、Sergei G. Zlotin
DOI:10.1002/ejoc.200900807
日期:2009.10
O-TMS-α,α-diphenyl-(S)-prolinol derivative bearing an ionicliquid fragment was synthesized for the first time and proven to be an efficient catalyst for the asymmetricMichaelreaction of aromatic α,β-unsaturated aldehydes with dialkylmalonates. The prepared catalyst can be recovered four times and used in the same reaction without a decrease in activity or a decrease in the enantioselectivity of
Lithium bis[(1R,5R)-3-aza-3-benzyl-1,5-diphenylpentan-1,5-diolato]-aluminium — A new heterobimetallic catalyst for Michael addition reactions
作者:G Manickam、G Sundararajan
DOI:10.1016/s0040-4020(99)00044-7
日期:1999.2
LiAlH4 to give the heterobimetallic complex 2 of the composition [(12-Al)Li]. Complex 2 was characterised by 1H-, 13C-, 27Al- and 7Li-NMR spectral data. Also, 2 when used in catalytic amounts accelerates Michaeladdition of malonates and thiophenol to α,β-unsaturated compounds like aldehydes, ketones, cyano and nitro compounds with high yield. Asymmetric induction in the Michael adducts has also been
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