corresponding succinimides in good yields and enantioselectivities. DFT calculations support the stereochemical results and the role played by the solvents. Chiralprimary amines containing the (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine scaffold and a pyrimidin-2-yl unit are synthesized and used as general organocatalysts for the Michael reaction of α-branched aldehydes to maleimides. The reaction
N-Primary-amine tetrapeptide-catalyzed highly asymmetric Michael addition of aliphatic aldehydes to maleimides
作者:Zhi-Hong Du、Wen-Juan Qin、Bao-Xiu Tao、Meng Yuan、Chao-Shan Da
DOI:10.1039/d0ob01457e
日期:——
highly asymmetric Michaeladdition reaction between maleimides and aliphatic aldehydes catalyzed by low-loading β-turn tetrapeptides with excellent yields and enantioselectivities at room temperature was reported. α-Branched and α-unbranched aldehydes both are suitable nucleophiles. N-Aryl, alkyl and hydrogen maleimides all are well tolerated and led to high yields and enantioselectivities. The transformation
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
Combining organocatalysis with photoorganocatalysis: photocatalytic hydroacylation of asymmetric organocatalytic Michael addition products
作者:Andriana Schiza、Nikoleta Spiliopoulou、Adelajda Shahu、Christoforos G. Kokotos
DOI:10.1039/c8nj04274h
日期:——
report a combination of these two stategies, taking advantage of an organocatalyticMichaeladdition of α,α-disubstituted aldehydes to maleimides as the first step and a photocatalytic hydroacylation of diisopropyl azodicarboxylate as the second step. Employing an amino acid as the organocatalyst for the asymmetricorganocatalytic part and an organic molecule as the photocatalyst, the combination of
Michael Addition of Ketones and Aldehydes to Maleimides Catalyzed by Modularly Designed Organocatalysts
作者:Savitha Muramulla、Jun-An Ma、John Cong-Gui Zhao
DOI:10.1002/adsc.201300041
日期:2013.5.3
primary α‐amino acids and Cinchona alkaloid thioureas were found to be excellent catalysts for the stereoselective Michaeladdition of enolizable ketones and aldehydes to maleimides. Using an MDO formed from quinidine thiourea and L‐2‐chlorophenylglycine, the corresponding Michaeladdition products, 3‐substituted succinimides, may be obtained in excellent yields and high enantio‐ and diastereoselectivities