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• 22252-14-8 (E)-3-(4-methylphenyl)-1-phenyl-2-propen-1-one 
• 4224-87-7 4-methyl-chalcone 
• 104-87-0 4-methyl-benzaldehyde 
• 98-86-2 acetophenone 
• 100-52-7 benzaldehyde 
• 622-97-9 1-ethenyl-4-methylbenzene 
• 14531-55-6 3,5-dimethyl-4-nitro-1H-pyrazole 
• 27729-96-0 1-phenyl-3-(p-methylphenyl)-2,3-epoxy-1-propanone 
• 70-11-1 α-bromoacetophenone 

Relevant academic research and scientific papers

Asymmetric epoxidation of α,β-unsaturated ketones catalyzed by rare-earth metal amides RE[N(SiMe3)2]3with chiral TADDOL ligands

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

Asymmetric Epoxidation of Enones Promoted by Dinuclear Magnesium Catalyst

Asymmetric synthesis with cheaper and non-toxic alkaline earth metal catalysts is becoming an important and sustainable alternative to conventional catalytic methodologies mostly relying on precious metals. In spite of some sustainable methods for enantioselective epoxidation of enones, the development of a well-defined and efficient catalyst based on magnesium complexes for these reactions is still a challenging task. In this perspective, we present the application of chiral dinuclear magnesium complexes for asymmetric epoxidation of a broad range of electron-deficient enones. We demonstrate that the in situ generated magnesium-ProPhenol complex affords enantioenriched oxiranes in high yields and with excellent enantioselectivities (up to 99% ee). Our extensive study verifies the literature data in this area and provides a step forward to better understand the factors controlling the oxygenation process. Elaborated catalyst offers mild reaction conditions and a truly wide substrate scope. (Figure presented.).

Organocatalytic Enantioselective γ-Elimination: Applications in the Preparation of Chiral Peroxides and Epoxides

An organocatalyzed enantioselective γ-elimination process has been achieved and applied in the kinetic resolution of peroxides to access chiral peroxides and epoxides. The reaction provided a pathway for the preparation of two useful synthetic and biologically important structural motifs through a single-step reaction. A range of substrates has been resolved with a selectivity factor up to 63. The obtained enantioenriched peroxides and epoxides allowed a series of transformations with retained optical purities.

Lanthanide complexes combined with chiral salen ligands: Application in the enantioselective epoxidation reaction of α,β-unsaturated ketones

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

Chiral calcium-catalyzed asymmetric epoxidation reactions using hydrogen peroxide as the terminal oxidant

Asymmetric epoxidation reactions of chalcone derivatives catalyzed by chiral calcium complexes using hydrogen peroxide were developed. The epoxidation reactions proceeded smoothly to afford the desired products in good yields with good enantioselectivitie

Bioinspired Manganese Complexes and Graphene Oxide Synergistically Catalyzed Asymmetric Epoxidation of Olefins with Aqueous Hydrogen Peroxide

Bioinspired manganese complexes of N4ligands and graphene oxide (GO) synergistically catalyze the highly enantioselective epoxidation of olefins (up to 99% ee), which is a rare example with GO as a co-catalyst in asymmetric catalysis. GO as a new and key additive not only successfully functions in catalytic amounts, but also has a positive effect for improving the enantioselectivity of the asymmetric epoxidation compared with the traditional stoichiometric organic carboxylic acid method [e.g., chalcone, 95% ee (3.5 mg GO) vs. 84% ee (5 equiv., 75 mg acetic acid), ethyl cinnamate, 84% ee (3.5 mg GO) vs. 19% ee (5 equiv., 75 mg acetic acid)]. The X-ray photoelectron spectroscopy (XPS) spectra of GO before and after the reaction indicate that the intensities of C–O become stronger after the reaction, which may have a certain relationship with hydrogen peroxide (H2O2) and gives a reasonable rationale for the large consumption of H2O2. Also, part of the hydrogen peroxide was used for the oxidation of GO. (Figure presented.).

Asymmetric Cascade Catalysis with Chiral Polyoxometalate-Based Frameworks: Sequential Direct Aldol and Epoxidation Reactions

Catalytic asymmetric cascade reactions in which the substrates are transferred through well-choreographed consecutive independent steps by a single catalyst have received increasing interest. By incorporating a chiral organocatalyst pyrrolidine, an oxidat

Enantioselective Epoxidation of Electron-Deficient Alkenes Catalyzed by Manganese Complexes with Chiral N4 Ligands Derived from Rigid Chiral Diamines

A series of tetradentate sp2N/sp3N hybrid chiral N4 ligands derived from rigid chiral diamines were synthesized, which enabled the first manganese-catalyzed enantioselective epoxidation of electron-deficient alkenes with hydrogen peroxide (H2O2) as an oxidant. The reaction furnishes enantiomerically pure epoxy amides, epoxy ketones as well as epoxy esters in good yields and excellent enantioselectivities (up to 99.9% ee) with lower catalyst loading. Preliminary studies on structure–activity relationship demonstrated that maintaining comparatively lower electron-donating ability of the sp3N and relatively higher electron-donating ability of sp2N of the N4 ligands is beneficial to getting higher activity and selectivity, thus providing us a new view to understand epoxidation with H2O2. (Figure presented.).

Proton-Promoted and Anion-Enhanced Epoxidation of Olefins by Hydrogen Peroxide in the Presence of Nonheme Manganese Catalysts

We report a remarkable Br?nsted acid effect in the epoxidation of olefins by nonheme manganese catalysts and aqueous hydrogen peroxide. More specifically, a mononuclear nonheme manganese complex bearing a tetradentate N4 ligand, MnII(Dbp-MCP)(OTf)2 (Dbp-MCP = (1R,2R)-N,N′-dimethyl-N,N′-bis((R)-(3,5-di-tert-butyl-phenyl)-2-pyridinylmethyl)cyclohexane-1,2-diamine; OTf- = CF3SO3-), is a highly efficient catalyst in the epoxidation of olefins by aqueous H2O2 in the presence of H2SO4 (1-3 mol %). The yields of epoxide products as well as the chemo- and enantioselectivities increase dramatically in the presence of H2SO4; no formation of epoxides is observed in the absence of H2SO4. In addition, the product yields and enantioselectivities are dependent significantly on the manganese catalysts and Br?nsted acids. The catalytic epoxidation of olefins by other oxidants, such as peracids, alkyl hydroperoxides, and iodosylbenzene, is also affected by the presence of H2SO4; product yields and enantioselectivities are high and similar irrespective of the oxidants in the presence of H2SO4, suggesting that a common epoxidizing intermediate is generated in the reactions of [MnII(Dbp-MCP)]2+ and the oxidants. Mechanistic studies, performed with 18O-labeled water (H218O) and cumyl hydroperoxide, reveal that a high-valent manganese-oxo species is formed as an epoxidizing intermediate via O-O bond heterolysis of Mn-OOH(R) species. The role of H2SO4 is proposed to facilitate the formation of a high-valent Mn-oxo species and to increase the oxidizing power and enantioselectivity of the Mn-oxo oxidant in olefin epoxidation reactions. Density functional theory (DFT) calculations support experimental results such as the formation of a Mn(V)-oxo species as an epoxidizing intermediate.

Quest for Efficient Catalysts based on Zinc tert-Butyl Peroxides for Asymmetric Epoxidation of Enones: C2- vs C1-Symmetric Auxiliaries

Zinc tert-butyl peroxide-based catalysts for the asymmetric epoxidation of enones using tert-butyl hydroperoxide as an oxidant have been developed. A comparative study of chiral monoanioninc N,N′-bidentate ligands, C2-symmetric bisoxazolinates and C1-symmetric enaminooxazolinates, revealed excellent performance of C1-symmetric auxiliary ligands on catalytic asymmetric epoxidation of enones (up to 96% yield, 91% ee).