α,β-dipeptides as chiralorganocatalysts in the asymmetricMichaeladditionreaction between enolizable aldehydes and N-arylmaleimides or nitroolefins is described. With N-arylmaleimides as substrates, the best results were achieved with dipeptide 2 as a catalyst in the presence of aq. NaOH. Whereas dipeptides 4 and 6 in conjunction with 4-dimethylaminopyridine (DMAP) and thiourea as a hydrogen bond
Asymmetric Michaeladdition reactions of aldehydes to nitroolefins have been successfully initiated by a series of primary amine thiourea bifunctional catalysts, with high enantioselectivities (90–98% ee) and excellent yields (80–96%). The privileged quinine scaffold was found to be essential to the reaction efficiency and enantioselectivity.
Enantioselective Michael Addition of Aldehydes to β-Nitrostyrenes Catalyzed by (S)-<i>N</i>
-(D-Prolyl)-1-triflicamido-3-phenylpropan-2-amine
作者:Amol B. Gorde、Ramesh Ramapanicker
DOI:10.1002/ejoc.201900719
日期:2019.8.7
A D‐prolinamide containing a triflicamide group as the H‐bond donor was developed to catalyze the asymmetricMichaeladdition of β‐nitroalkenes with aldehydes. Very high enantioselectivity and yields are achieved using 10 mol% of the catalyst at r.t. in toluene.
Asymmetric Michael reaction between aldehydes and nitroalkanes promoted by pyrrolidine-containing C2-symmetric organocatalysts
作者:K. A. Bykova、A. A. Kostenko、A. S. Kucherenko、S. G. Zlotin
DOI:10.1007/s11172-019-2568-2
日期:2019.7
Bifunctional C2-symmetric organocatalysts derived from chiral 1,2-diaminoethanes and (S)-2-aminomethylpyrrolidine were fi rst used for promoting the asymmetricMichael addition of aliphatic aldehydes to nitroalkenes. The synthesized enantioenriched (up to 82% ee) products can be transformed into various biologically active γ-aminobutyric acid derivatives.
<scp>d</scp>-Prolyl-2-(trifluoromethylsulfonamidopropyl)pyrrolidine: An Organocatalyst for Asymmetric Michael Addition of Aldehydes to β-Nitroalkenes at Ambient Conditions
作者:Amol B. Gorde、Ramesh Ramapanicker
DOI:10.1021/acs.joc.8b02945
日期:2019.2.1
yrrolidines and their d-prolinamides were prepared and screened as organocatalysts for the Michael addition reaction of aldehydes with β-nitroalkenes at rt and without the use of additives. d-Prolyl-2-(trifluoromethylsulfonamidopropyl)pyrrolidine was found to be the best among the molecules studied, which yielded γ-nitro aldehydes in very high yields (up to 95%), with high diastereoselectivity (up