204450-47-5Relevant academic research and scientific papers
Mechanistic insights from reaction progress kinetic analysis of the polypeptide-catalyzed epoxidation of chalcone
Mathew, Suju P.,Gunathilagan, Suthahari,Roberts, Stanley M.,Blackmond, Donna G.
, p. 4847 - 4850 (2005)
(Chemical Equation Presented) Reaction progress kinetic analysis of the poly(L)-leucine (PLL)-catalyzed epoxidation of substituted chalcones 1a-1c helps to refine an earlier mechanistic proposal by demonstrating that the reaction proceeds via reversible a
Asymmetric epoxidation of α,β-unsaturated ketones catalyzed by rare-earth metal amides RE[N(SiMe3)2]3with chiral TADDOL ligands
Shan, Haiwen,Lu, Chengrong,Zhao, Bei,Yao, Yingming
, p. 1043 - 1053 (2021/01/25)
The catalytic asymmetric epoxidation of α,β-unsaturated ketones by tert-butylhydroperoxide (TBHP) has been well established using rare-earth metal amides RE[N(SiMe3)2]3 (RE = La(1), Nd(2), Sm(3), Y(4), Yb(5)) with chiral TADDOL ligands. It was found that
Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Using Amide-Based Cinchona Alkaloids as Hybrid Phase-Transfer Catalysts
Jurczak, Janusz,Majdecki, Maciej,Tyszka-Gumkowska, Agata
, (2020/11/13)
A series of 20 one chiral epoxides were obtained with excellent yields (up to 99%) and enantioselectivities (up to >99% ee) using hybrid amide-based Cinchona alkaloids. Our method is characterized by low catalyst loading (0.5 mol %) and short reaction times. Moreover, the epoxidation process can be carried out in 10 cycles, without further catalyst addition to the reaction mixture. This methodology significantly enhance the scale of the process using very low catalyst loading.
Lanthanide complexes combined with chiral salen ligands: Application in the enantioselective epoxidation reaction of α,β-unsaturated ketones
Xia, Xuexiu,Lu, Chengrong,Zhao, Bei,Yao, Yingming
, p. 13749 - 13756 (2019/05/16)
Readily available lanthanide amides Ln[N(SiMe3)2]3 (Ln = Nd (1), Sm (2), Eu (3), Yb (4), La (5)), combined with chiral salen ligands H2La ((S,S)-N,N′-di-(3,5-disubstituted-salicylidene)-1,2-cyclohexan
Crown-ether-modified cyclic dipeptides as supramolecular chiral catalysts
Bérubé, Christopher,Voyer, Normand
, p. 184 - 195 (2017/10/26)
With the objective to develop supramolecular catalysts for useful chemical transformations, we report here a rapid and efficient solid-phase synthesis of novel cyclic dipeptides (crown-CDPs) with a diversity of L-DOPA derived crown ether substituents and
Revisiting the Juliá-Colonna enantioselective epoxidation: Supramolecular catalysis in water
Bérubé, Christopher,Barbeau, Xavier,Lagüe, Patrick,Voyer, Normand
supporting information, p. 5099 - 5102 (2017/07/12)
We describe an efficient epoxidation process leading to chiral epoxyketones using the reusable homo-oligopeptide poly-l-leucine (PLL) in pure water, without any organic co-solvent. A range of substituted epoxyketones can be accessed with good conversions and high enantioselectivities. Based on the experimental results and computational studies, we propose a mechanism that demonstrates the importance of both the α-helical structure and the presence of a hydrophobic groove of the homo-oligopeptide catalyst for reactivity and selectivity.
Biomimetic epoxidation in aqueous media catalyzed by cyclic dipeptides
Bérubé, Christopher,Voyer, Normand
supporting information, p. 395 - 403 (2016/04/05)
We have developed a practical epoxidation of electron-deficient enones in aqueous media using cyclic dipeptides as bioinspired green catalyst. Optimizing the reaction conditions in a triphasic system led to efficient conditions providing epoxides with good enantioselectivities. Depending on the catalyst substituent chirality, both enantiomers are obtained. The cyclic rigidity impacts significantly the enantioselectivity.
Synthesis and Catalytic Asymmetric Applications of Quinazolinol Ligands
Karakaya, Idris,Karabuga, Semistan,Mart, Mehmet,Altundas, Ramazan,Ulukanli, Sabri
, p. 1719 - 1726 (2016/05/24)
A range of chiral quinazolinol ligands were efficiently synthesized and subsequently investigated for catalytic chiral induction in both the asymmetric phenylation of aryl aldehydes and the asymmetric epoxidation of chalcones. Encouragingly, high enantioselectivities (up to 95%) and yields (up to 98%) were achieved under the optimized reaction conditions.
Chiral octahedral complexes of Co(iii) as catalysts for asymmetric epoxidation of chalcones under phase transfer conditions
Larionov, Vladimir A.,Markelova, Elina P.,Smol'yakov, Alexander F.,Savel'yeva, Tat'yana F.,Maleev, Victor I.,Belokon, Yuri N.
, p. 72764 - 72771 (2015/09/15)
Stereochemically inert and positively charged chiral complexes of Co(iii) were shown to catalyze the asymmetric epoxidation of chalcones with H2O2 under phase transfer conditions. The reaction products had enantiomeric purities of up to 55%. It was also shown that complex 1a I- catalyzed the coupling reaction of a resulting epoxide with CO2 (conversion 72%).
Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Catalyzed by Rare-Earth Amides [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 with Phenoxy-Functionalized Chiral Prolinols
Zeng, Chao,Yuan, Dan,Zhao, Bei,Yao, Yingming
supporting information, p. 2242 - 2245 (2015/05/13)
A simple and efficient catalytic enantioselective epoxidation of α,β-unsaturated ketones has been successfully developed, which was catalyzed by rare-earth metal amides [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 (RE = Yb (1), La (2), Sm (3), Y (4), Lu (5)) in the presence of phenoxy-functionalized chiral prolinols at room temperature using tert-butylhydroperoxide (TBHP) as the oxidant. The combination of an Yb-based amide 1 and a chiral proligand (S)-2,4-di-tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol) performed very well, and both the yields and the enantiomeric excess of the chiral epoxides reached up to 99% and 99% ee. (Figure Presented).
