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
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
Unifying Metal- and Organocatalysis for Asymmetric Oxidative Iminium Activation: A Relay Catalytic System Enabling the Combined Allylic Oxidation of Alcohols and Prolinol Ether Catalyzed Iminium Reactions
作者:Magnus Rueping、Henrik Sundén、Erli Sugiono
DOI:10.1002/chem.201102551
日期:2012.3.19
A multicatalytic system consisting of tetrapropylammonium perruthenate/N‐methylmorpholine N‐oxide (TPAP/NMO) as oxidant, and diarylprolinol TMS‐ether as chiral amine catalyst, has been developed and applied in the efficient construction of valuable chiral molecules. The one‐pot domino reactions elaborated in the present study are based on the in situ generation of α,β‐unsaturated aldehydes from allylic
A Recyclable Chiral 2‐(Triphenylmethyl)pyrrolidine Organocatalyst Anchored to [60]Fullerene
作者:Cristian Rosso、Marco G. Emma、Ada Martinelli、Marco Lombardo、Arianna Quintavalla、Claudio Trombini、Zois Syrgiannis、Maurizio Prato
DOI:10.1002/adsc.201900009
日期:2019.6.18
[60]fullerene via click chemistry provides a highlyefficient supported enantioselectiveorganocatalyst, which was successfully exploited in a Michaeladdition of malonates to cinnamaldehydes, via iminium ion activation. The supported organocatalyst was recycled up to six times, with only a moderate decrease in terms of activity and with no loss in enantioselectivity.