807630-81-5Relevant articles and documents
Synthesis of Epoxides from Alkyl Bromides and Alcohols with in Situ Generation of Dimethyl Sulfonium Ylide in DMSO Oxidations
Zhang, Zhi-Wei,Li, Hai-Bo,Li, Jin,Wang, Cui-Cui,Feng, Juan,Yang, Yi-Hua,Liu, Shouxin
, p. 537 - 547 (2020/01/02)
Direct conversion of the readily available alkyl bromides and alcohols to value-added epoxides using dimethyl sulfoxide (DMSO) under mild reaction conditions has been developed. Benzyl and allyl bromides, and activated and unactivated alcohols all proceeded smoothly to give epoxides in high to excellent yield. Dimethyl sulfide, generated by DMSO oxidations, was in situ elaborated to form the substituted dimethyl sulfonium ylide species that participates in the Corey-Chaykovsky epoxidation in a domino and one-pot fashion, respectively.
Method for directly synthesizing epoxy compound from benzyl bromine compound
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Paragraph 0080-0086, (2019/08/30)
The invention discloses a method for directly synthesizing an epoxy compound from a benzyl bromine compound. According to the method, by using a benzyl bromine compound as a reactant and dimethyl sulfoxide as an oxidizing agent, an epoxy compound is directly synthesized under the action of a solvent and alkali. The synthetic route of the method is as follows: the benzyl bromine compound is dissolved in a reaction solvent to obtain A; the oxidizing agent dimethyl sulfoxide and alkali are added into the A and a reaction is carried out to obtain the epoxy compound. The method is simple and is convenient to operate; the reaction condition is mild; the reaction process is easy to control; the reaction process is safe and environmentally-friendly; the reaction reagents are cheap and easily available; and the reaction yield is high.
Redesign of a Pyrylium Photoredox Catalyst and Its Application to the Generation of Carbonyl Ylides
Alfonzo, Edwin,Alfonso, Felix Steven,Beeler, Aaron B.
, p. 2989 - 2992 (2017/06/07)
We report the exploration into photoredox generation of carbonyl ylides from benzylic epoxides using newly designed 4-mesityl-2,6-diphenylpyrylium tetrafluoroborate (MDPT) and 4-mesityl-2,6-di-p-tolylpyrylium tetrafluoroborate (MD(p-tolyl)PT) catalysts. These catalysts are excited at visible wavelengths, are highly robust, and exhibit some of the highest oxidation potentials reported. Their utility was demonstrated in the mild and efficient generation of carbonyl ylides from benzylic epoxides that otherwise could not be carried out by current common photoredox catalysts.
Biomimetic iron-catalyzed asymmetric epoxidation of aromatic alkenes by using hydrogen peroxide
Gelalcha, Feyissa Gadissa,Anilkumar, Gopinathan,Tse, Man Kin,Brueckner, Angelika,Beller, Matthias
supporting information; experimental part, p. 7687 - 7698 (2009/08/07)
A novel and general biomimetic non-heme Fe-catalyzed asymmetric epoxidation of aromatic alkenes by using hydrogen peroxide is reported herein. The catalyst consists of ferric chloride hexahydrate (FeCl3·OH 2O), pyridine-2,6-dicarboxylic acid (H2-(pydic)), and readily accessible chiral N-arenesulfonyl-N′-benzyl-substituted ethylenediamine ligands. The asymmetric epoxidation of styrenes with this system gave high conversions but poor enantiomeric excesses (ee), whereas larger alkenes gave high conversions and ee values. For the epoxidation of trans-stilbene (1a), the ligands (S,S)-N-(4-toluenesulfonyl)-1,2- diphenylethylenediamine ((S,S)-4a) and its N′-benzylated derivative ((S,S)-5a) gave opposite enantiomers of trans-stilbene oxide, that is, (S,S)-2a and (R,R)-2a, respectively. The enantioselectivity of alkene epoxidation is controlled by steric and electronic factors, although steric effects are more dominant. Preliminary mechanistic studies suggest the in situ formation of several chiral Fe-complexes, such as [FeCl(L*)2-(pydic)] ·HCl (L* = (S,S)-4a or (S,S)-5a in the catalyst mixture), which were identified by ESIMS. A UV/Vis study of the catalyst mixture, which consisted of FeCl3·6H2O, H2(pydic), and (S,S)-4a, suggested the formation of a new species with an absorbance peak at λ = 465 nm upon treatment with hydrogen peroxide. With the aid of two independent spin traps, we could confirm by EPR spectroscopy that the reaction proceeds via radical intermediates. Kinetic studies with deuterated styrenes showed inverse secondary kinetic isotope effects, with values of k H/kD = 0.93 for the β carbon and kH/k D=0.97 for the a carbon, which suggested an unsymmetrical transition state with stepwise O transfer. Competitive epoxidation of para-substituted styrenes revealed a linear dual-parameter Hammett plot with a slope of 1.00. Under standard conditions, epoxidation of la in the presence of ten equivalents of H218O resulted in an absence of the isotopic label in (S,S)-2a. A positive non-linear effect was observed during the epoxidation of la in the presence of (S,S)-5a and (R,R)-5a.
Iron-catalyzed asymmetric epoxidation of aromatic alkenes using hydrogen peroxide
Gelalcha, Feyissa Gadissa,Bitterlich, Bianca,Anilkumar, Gopinathan,Man, Kin Tse,Beller, Matthias
, p. 7293 - 7296 (2008/09/18)
(Chemical Equation Presented) Ironing out the wrinkles: Highly enantioselective catalytic asymmetric epoxidation of aromatic alkenes with hydrogen peroxide proceeds smoothly in the presence of a catalyst system consisting of ferric hexahydrate, pyridine-2,6-dicarboxylic acid, and the novel chiral ligand 1 in 2-methylbutane-2-ol solvent at room temperature within 1 h (see scheme; Bn = benzyl).
A novel epoxidation reaction of olefins using a combination of chloramine-M, benzaldehyde, and benzyltriethylammonium chloride
Yang, Dan,Zhang, Chi,Wang, Xue-Chao
, p. 4039 - 4043 (2007/10/03)
A combination of Chloramine-M (CH3SO2NClNa), benzaldehyde, and benzyltriethylammonium chloride (BTEAC) was found to epoxidize a wide range of olefins. While epoxidation of trans-olefins provided exclusively trans- epoxides, cis-olefins (cis-stilbene, cis-β-methylstyrene, and 4-cis-octene) gave trans-epoxides as major products. Good to excellent diastereoselectivities were obtained for epoxidation of two substituted cyclohexenes. Chloramine-T was found to give a slower reaction than Chloramine-M. cis-N-Sulfonyloxaziridine D is proposed to be the epoxidizing agent in this novel epoxidation reaction on the basis of the mechanistic studies.
