115794-66-6Relevant articles and documents
A new chiral diiron catalyst for enantioselective epoxidation
Marchi-Delapierre, Caroline,Jorge-Robin, Adeline,Thibon, Aurore,Menage, Stephane
, p. 1166 - 1168 (2007)
The dinuclear chiral complex Fe2O(bisPB)4(X) 2(ClO4)4 (X = H2O or CH 3CN) catalyzes with high efficiency (up to 850 TON) and moderate enantioselectivity (63%) the epoxidation of
Mechanism of Oxygen Atom Transfer from FeV(O) to Olefins at Room Temperature
Singh, Kundan K.,Tiwari, Mrityunjay K.,Dhar, Basab B.,Vanka, Kumar,Sen Gupta, Sayam
, p. 6112 - 6121 (2015)
In biological oxidations, the intermediate FeV(O)(OH) has been proposed to be the active species for catalyzing the epoxidation of alkenes by nonheme iron complexes. However, no study has been reported yet that elucidates the mechanism of direct O-atom transfer during the reaction of FeV(O) with alkenes to form the corresponding epoxide. For the first time, we study the mechanism of O-atom transfer to alkenes using the FeV(O) complex of biuret-modified Fe-TAML at room temperature. The second-order rate constant (k2) for the reaction of different alkenes with FeV(O) was determined under single-turnover conditions. An 8000-fold rate difference was found between electron-rich (4-methoxystyrene; k2 = 216 M-1 s-1) and electron-deficient (methyl trans-cinnamate; k2 = 0.03 M-1 s-1) substrates. This rate difference indicates the electrophilic character of FeV(O). The use of cis-stilbene as a mechanistic probe leads to the formation of both cis- and trans-stilbene epoxides (73:27). This suggests the formation of a radical intermediate, which would allow C-C bond rotation to yield both stereoisomers of stilbene-epoxide. Additionally, a Hammett ρ value of -0.56 was obtained for the para-substituted styrene derivatives. Detailed DFT calculations show that the reaction proceeds via a two-step process through a doublet spin surface. Finally, using biuret-modified Fe-TAML as the catalyst and NaOCl as the oxidant under catalytic conditions epoxide was formed with modest yields and turnover numbers. (Graph Presented).
Efficient magnetic and recyclable SBILC (supported basic ionic liquid catalyst)-based heterogeneous organocatalysts for the asymmetric epoxidation of trans-methylcinnamate
Candu,Rizescu,Podolean,Tudorache,Parvulescu,Coman
, p. 729 - 737 (2015)
A green alternative, based on the use of an efficient and recyclable chiral ketone@SBILC@MWCNT@Fe3O4 catalytic system (Y = 35%, S = 100% and ee = 100%), was developed for the asymmetric epoxidation of trans-methylcinnamate to (2R,3S)
Ligand and pH influence on manganese-mediated peracetic acid epoxidation of terminal olefins
Murphy, Andrew,Pace, Allyson,Stack, T. Daniel P.
, p. 3119 - 3122 (2004)
(Chemical Equation Presented) Nineteen MnII complexes were screened for the catalytic epoxidation of terminal olefins using peracetic acid. Few of these complexes are efficient catalysts at pH 2, but many are effective at 1 mol % catalyst loading at pH 4. With 0.1 mol % loading, four complexes epoxidize 1-octene in ～80% yield in 5 min. The relative reactivity of the catalysts toward different olefins was probed using a multicomponent intermolecular competition reaction.
Postsynthetic modification of a metal-organic framework (MOF) structure for enantioselective catalytic epoxidation
Candu, Natalia,Tudorache, Madalina,Florea, Mihaela,Ilyes, Elena,Vasiliu, Florin,Mercioniu, Ionel,Coman, Simona M.,Haiduc, Ionel,Andruh, Marius,Parvulescu, Vasile I.
, p. 443 - 450 (2013)
Postsynthetic modification of [Cu2(mand)2(hmt)] (mand=mandelic acid, hmt=hexamethylenetetramine) with a chiral, dimeric chromium(III)-salen complex led to a robust structure. Characterization of this new material showed that it perfectly preserved the textural and structural properties of the parent metal-organic framework (MOF). Although epoxidation of trans-methyl cinnamate with hydrogen peroxide led to copper leaching of 2-3 %, experiments performed with N-methylmorpholine-N-oxide indicated no leaching, even after 72 h of exposure. The obtained chiral MOF is an effective catalyst for the enantioselective epoxidation of trans-methyl cinnamate and leads to (2R,3S)-phenylglycidate with a high enantiomeric excess at room temperature. Transformed and ready for action! Postsynthetic modification of [Cu 2(mand)2(hmt)] (mand=mandelic acid, hmt= hexamethylenetetramine) results in an effective catalyst (see picture) for the enantioselective epoxidation of trans-methyl cinnamate to provide methyl (2R,3S)-phenylglycidate with a high ee value at room temperature. Copyright
MnII complexes with tetradentate N4 ligands: Highly efficient catalysts for the epoxidation of olefins with H2O 2
Yu, Songjie,Miao, Cheng-Xia,Wang, Daqi,Wang, Shoufeng,Xia, Chungu,Sun, Wei
, p. 185 - 191 (2012)
A series of Mn-complexes with tetradentate N4 ligands, introducing aromatic groups into 2-pyridylmethyl positions of N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine (mep), N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)cyclohexane-trans-diamine (mcp), have been synthesized and applied for epoxidation of olefins using H 2O2 as the oxidant. The Mn-complexes still possessed an octahedral mononuclear structure in a cis-α topology. These complexes showed good regioselectivity, high yields and turnover frequency (even up to 228,000 h-1) with low catalyst loading (0.1-0.01 mol%) for epoxidation of a family of olefins (including internal aromatic olefins, internal and terminal aliphatic olefins and diolefins).
Synthesis of enantiomerically pure forms of trans-3-phenylglycidic acid.
Plucinska, Krystyna,Kasprzykowski, Franciszek,Kozian, Elzbieta
, p. 861 - 864 (1997)
Trans-(2R,3S)- and (2S,3R)-3-phenylglycidic acids were obtained as pure crystals. The optical properties and chemical stability were characterized. The absolute configuration of the trans(+)- and trans-(-) isomers was established by means of chemical correlation.
New organic-inorganic LDH composites: Synthesis, characterization and catalytic behavior in the green epoxidation of α, β-unsaturated esters
Candu, Natalia,Paul, Diana,Marcu, Ioan-Cezar,Tudorache, Madalina,Parvulescu, Vasile I.,Coman, Simona M.
, p. 127 - 132 (2018)
New organic-inorganic based LDH composites have been prepared using different methodologies, ie the ion-exchange method (Org@LDH-exch), the reconstruction (Org@LDH-mem) and the direct intercalation (Org@LDH-inter) method, respectively. Irrespective of the procedure, the –C[dbnd]O group of levulinate moiety was envisaged as a potential active organocatalyst in the epoxidation of trans-methylcinnamate to methyl-phenyl-glycidate. The characterisation of these materials through adsorption-desorption isotherms of nitrogen at ?196 °C, XRD, TG-DTA and DRIFT confirmed a successful intercalation only for Org@LDH-inter. The reactions were carried out via in situ generated dioxiranes using levulinate as active organocatalyst and H2O2/acetonitrile mixture as oxidant. Intercalated levulinate in aminoterephthalate/LDH structure led to conversions up to 25% with a total selectivity to methyl-phenyl-glycidate. Besides this, the heterogeneous organocatalyst behave as a green system: the constitutive levulinic acid represents one of the most important renewable platform molecules, while replacing the Oxone reagent with the more benign hydrogen peroxide and the substitution of an inorganic soluble base with the basic function of the LDH-support afford a more benign system.
Dioxirane-mediated heterogeneous epoxidations with potassium caroate: A solid catalyst bearing anchored ketone moieties
D'Accolti, Lucia,Annese, Cosimo,De Riccardis, Alberto,De Giglio, Elvira,Cafagna, Damiana,Fanelli, Fiorenza,Fusco, Caterina
, p. 4616 - 4621,6 (2012)
A new hybrid material (3) consisting of trifluoromethyl ketone (TFMK) moieties, immobilized on silica through an appropriate spacer, was synthesized and characterized. Lacking easily oxidizable functionalities in the spacer chain, this material proved to be an excellent catalyst in heterogeneous epoxidations with potassium caroate (KHSO5), surpassing other reported catalysts in performance and stability. The efficiency of silica-supported catalyst 3 could be assessed upon carrying out the selective dioxirane-mediated epoxidation of representative alkenes in high yields. The solid catalyst could then be recovered and reused in a number of consecutive oxidation cycles. The synthesis of a new hybrid, which presents trifluoromethyl ketone moieties anchored on silica gel through a short spacer, is reported. Lacking easily oxidizable functionalities in the linker chain, this solid material is an efficient catalyst in dioxirane-mediated heterogeneous epoxidations using potassium caroate. Copyright
Regioselective syntheses of 3-hydroxy-4-aryl-3,4,5-trihydro-2H-benzo[b][1,4]diazepin-2(1H)-ones and 3-benzylquinoxalin-2(1H)-ones from arylglycidates when exposed to 1,2-diaminobenzenes
Mamedov, Vakhid A.,Mamedova, Vera L.,Syakaev, Victor V.,Voronina, Julia K.,Mahrous, Essam M.,Korshin, Dmitry E.,Latypov, Shamil K.,Sinyashin, Oleg G.
, (2020/09/10)
Representatives of two pharmacologically significant classes of compounds – 3-hydroxy-4-aryl-3,4,5-trihydro-2H-benzo[b][1,4]diazepin-2(1H)-ones and 3-benzylquinoxalin-2(1H)-ones – obtained in reactions of 1,2-diaminobenzenes with methyl 3-arylglycidates in boiling acetic acid. Substituents in arylglycidates determine the direction of processes. Electron withdrawing substituents (NO2), halogen atoms (Cl, Br, F), as well as the absence of substituents, provide the formation of benzo[b][1,4]diazepin-2(1H)-one derivatives, and electron donating groups (OMe, Me) contribute to the formation of 3-benzylquinoxalin-2(1H)-ones. As a result, a new rare representatives of 3-hydroxy-4-aryl-3,4,5-trihydro-2H-benzo[b][1,4]diazepin-2(1H)-ones were obtained and a new method for producing 3-benzylquinoxalin-2(1H)-ones has been proposed.
