648430-79-9Relevant academic research and scientific papers
Helical-Peptide-Catalyzed Enantioselective Michael Addition Reactions and Their Mechanistic Insights
Ueda, Atsushi,Umeno, Tomohiro,Doi, Mitsunobu,Akagawa, Kengo,Kudo, Kazuaki,Tanaka, Masakazu
, p. 6343 - 6356 (2016/08/16)
Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities (up to 99%). On the basis of X-ray crystallographic analysis and depsipeptide study, the amide protons, N(2)-H and N(3)-H, at the N terminus in the α-helical peptide catalyst were crucial for activating Michael donors, while the N-terminal primary amine activated Michael acceptors through the formation of iminium ion intermediates.
(1R,2R)-(+)-(1,2)-DPEN-Bonded Sulfonic Acid Resin: A Trifunctional Heterogeneous Catalyst for Asymmetric Michael Additions of Acetone to Nitroolefins
Zhang, Chao,Li, Jing,Tian, Jun,Fang, Wangwang,Li, Yang,Chen, Ligong,Yan, Xilong
, p. 1248 - 1258 (2015/03/30)
Based on (1R,2R)-(+)-(1,2)-DPEN skeleton, a series of primary amine-sulfamide bifunctional catalysts were synthesized, which exhibited excellent catalytic performance in the Michael addition of acetone to β-nitrostyrene. Therefore, a trifunctional heterogeneous catalyst was designed and prepared by simple N-sulfonyl reaction of (1R,2R)-(+)-(1,2)-DPEN and sulfonyl chloride resin. It was employed for the aforementioned addition without any additive and satisfactory results (80.5% conversion; 84.3% ee) were obtained. Meanwhile, the structural and textural properties of the catalyst were characterized by infrared spectroscopy (FT-IR), elemental analysis, SEM, and N2 adsorption and desorption experiments. Finally, the generality of the catalyst was investigated.
Highly enantioselective conjugate addition of nitroalkanes to enones catalyzed by cinchona alkaloid derived primary amine
Liu, Wenjing,Mei, Desheng,Wang, Wei,Duan, Wenhu
supporting information, p. 3791 - 3793 (2013/07/05)
A cinchona alkaloid derived primary amine catalyzed conjugate addition of nitroalkanes to enones is described. The process affords the Michael adducts in good yield and with up to 99% ee for both acyclic and cyclic enones.
Primary amine-thioureas with improved catalytic properties for "difficult" Michael reactions: Efficient organocatalytic syntheses of (S)-baclofen, (R)-baclofen and (S)-phenibut
Tsakos, Michail,Kokotos, Christoforos G.,Kokotos, George
supporting information; experimental part, p. 740 - 746 (2012/05/04)
Among the class of primary amine-thioureas based on tert-butyl esters of α-amino acids, the most efficient organocatalyst for "difficult" Michael reactions was identified. The derivative based on (S)-di-tert-butyl aspartate and (1R,2R)-diphenylethylenedia
Modular bifunctional chiral thioureas as versatile organocatalysts for highly enantioselective aza-Henry reaction and michael addition
Li, Hua,Zhang, Xu,Shi, Xin,Ji, Nan,He, Wei,Zhang, Shengyong,Zhang, Bangle
, p. 2264 - 2274 (2012/11/06)
A series of new modular bifunctional chiral thiourea organocatalysts were synthesized from natural Cinchona alkaloids and amino acids, and their performance in the aza-Henry reaction of nitroalkanes to imines, the Michael addition of acetylacetone to nitroolefins and the Michael addition of acetone to nitroolefins was investigated. Under the mild conditions, the important building blocks β-nitro amines and γ-nitro carbonyl compounds could be obtained in good yields (up to 95%) with excellent enantioselectivities (up to 99% ee) and diastereoselectivity (up to 17:1). Copyright
A recyclable organocatalyst for asymmetric Michael addition of acetone to nitroolefins
Lu, Aidang,Liu, Tao,Wu, Ronghua,Wang, Youming,Wu, Guiping,Zhou, Zhenghong,Fang, Jianxin,Tang, Chuchi
experimental part, p. 3872 - 3879 (2011/07/08)
Based on different chiral diamine skeletons, a series of bifunctional primary amine-thiophosphoramides were synthesized and screened as the catalysts for the asymmetric Michael addition of acetone to both aromatic and aliphatic nitroolefins. Under the cat
Asymmetric conjugate addition of nitromethane to enones catalyzed by chiral N,N'-dioxide-scandium(III) complexes
Wang, Liwei,Zhang, Qi,Zhou, Xin,Liu, Xiaohua,Lin, Lili,Qin, Bo,Feng, Xiaoming
supporting information; experimental part, p. 7696 - 7699 (2010/09/10)
(Chemical Equation Representation)Chalk it up as a "Sc"andal: The asymmetric conjugate addition of chalcone and "cinnamone" derivatives to nitromethane has been realized by using a simple and efficient scandium(III)N,N'-dioxide complex as the catalyst (se
Highly enantioselective michael addition of acetone to nitro olefins catalyzed by chiral bifunctional primary amine-thiophosphoramide catalyst
Lu, Aidang,Liu, Tao,Wu, Ronghua,Wang, Youming,Zhou, Zhenghong,Wu, Guiping,Fang, Jianxin,Tang, Chuchi
experimental part, p. 5777 - 5781 (2011/01/04)
A series of bifunctional primary amine-thiophosphoramides were synthesized, which proven to be effective organocatalysts for the asymmetric Michael reaction of acetone to both aryl and alkyl nitro olefins in the presence of phenol as a protic additive. The corresponding adducts were obtained in excellent chemical yields (up to >99%) with excellent enantioselectivities (up to 97% ee). A novel chiral phosphoramide functions well as an efficient bifunctional organocatalyst for the asymmetric Michael addition of acetone, one of the most challenge substrate in Michael addition, to nitro olefinsto afford the corresponding syntheticvaluable γ-nitro ketones in good to excellent yield with high levels of enantioselectivities (up to 97% ee, respectively).
Noyort's Ts-DPEN ligand: Simple yet effective catalyst for the highly enantioselective michael addition of acetone to nitroalkenes
Peng, Lin,Xu, Xiao-Ying,Wang, Liang-Liang,Huang, Jun,Bai, Jian-Fei,Huang, Qing-Chun,Wang, Li-Xin
experimental part, p. 1849 - 1853 (2010/07/18)
Highly enantioselective Michael addition of acetone to a variety of nitroalkenes promoted by simple chiral primary amine bifunctional catalysts (e.g., Noyori's Ts-DPEN ligand) together with terephthalic acid in excellent yields (84-99%) and enantioselectivities (93-98 % ee) is reported.
C3-symmetric proline-functionalized organocatalysts: Enantioselective michael addition reactions
Moorthy, Jarugu Narasimha,Saha, Satyajit
experimental part, p. 6359 - 6365 (2011/03/17)
C3-Symmetric, tripodal catalyst 4 based on 1,3,5- triethylbenzene, which incorporates the features of a molecular receptor, is shown to catalyze Michael addition reactions ofcarbonyl compounds to β-nitrostyrenes in a high stereoselectivity (up to 99:1a dr and up to 98%ee). Copyright
