10282-18-5Relevant articles and documents
Exocyclic iminium salts as catalysts for alkene epoxidation by Oxoneρ
Armstrong, Alan,Ahmed, Ghafoor,Garnett, Ian,Goacolou, Katell,Wailes, J. Steven
, p. 2341 - 2352 (1999)
Exocyclic iminium salts are evaluated as catalysts for alkene epoxidation by Oxone, presumed to proceed via the corresponding oxaziridinium species. Iminium triflate salts derived from pyrrolidine and electron poor aromatic aldehydes were found to be good catalysts. Attempts to prepare chiral variants of these iminium salts were largely unsuccessful, presumably due to their ready hydrolysis.
Design of efficient ketone catalysts for epoxidation by using the field effect
Yang, Dan,Yip, Yiu-Chung,Jiao, Guan-Sheng,Wong, Man-Kin
, p. 8952 - 8956 (1998)
By using the field effect (through-space charge-dipole or dipole-dipole interactions), efficient ketone catalysts 7 and 10 were developed for in situ epoxidation of olefins with Oxone. With either ketone 7 (10-20 mol %) or 10 (5-10 mol %) as catalyst, epoxidation of various olefins (2 mmol scale) at room temperature with 1.5 equiv of Oxone was complete in a short period of time with excellent isolated yields of epoxides (80-97%) and good ketone recovery (~80%) Furthermore, the in situ epoxidation of olefins can be performed on a large scale (20-100 mmol) directly with 5 mol % of commercially available tetrahydrothiopyran-4-one, which is oxidized by Oxone to ketone 10 during the epoxidation reactions.
Formation of epoxides and N-arylaziridines via a simple Mg-Barbier reaction in DMF
Oudeyer, Sylvain,Léonel, Eric,Paugam, Jean Paul,Nédélec, Jean-Yves
, p. 919 - 923 (2014)
The Mg-activation of benzal bromide 2b in DMF in the presence of carbonyl compounds 1 or imines 4 leads to epoxides 3 and N-arylaziridines 5, respectively, with acceptable isolated yields. It was found that DMF is likely involved in this process to form a nucleophilic intermediate by reaction with a first generated electrophilic carbene. Results obtained in this chemical approach are compared to those obtained using electrochemical activation, also in DMF.
An effective dual copper-and sulfide-catalytic system for the epoxidation of aldehydes with phenyldiazomethane
Pereira, Ana,Martín, Carmen,Maya, Celia,Belderrain, Tomás R.,Pérez, Pedro J.
, p. 2942 - 2951 (2013)
Epoxides have been obtained from alde-hydes and phenyldiazomethane using catalytic amounts of both the copper homoscorpionate com-plexes Tp xCuL (Tpx = homoscorpionate ligand; L = acetonitrile or tetrahydrofuran, THF) and dimethyl sulfide (SMe2) in high yields and diasteroselectivities, and with activities higher (TOF = 46 h-1) than those already known with rhodium-or copper-based cata-lysts. Among the copper(I) homoscorpionate com-plexes tested, TpBr3Cu(NCCH 3) showed the highest catalytic activity under mild conditions. The catalytic activity is controlled by electronic effects induced by the Tp x ligand as well as by the stability of the TpxCu(SR 2) adducts. Indeed, in the case of TpMs as ligand, the TpMsCu(THT) (THT = tetrahydrothio-phene) and Tp MsCu(SMe2) species could be isolated as very stable crystalline solids, the molecular struc-ture of the former being confirmed by single-crystal X-ray diffraction analysis. The in situ generation of PhCHN 2 from benzaldehyde tosylhydrazone sodium salt at 60 °C in methyl tert-butyl ether as solvent and TpMsCu(THF) as the catalyst also showed high cata-lytic activities, improving those already reported with copper-based catalysts.
Non-aqueous iminium salt mediated catalytic asymmetric epoxidation
Bulman Page, Philip C.,Buckley, Benjamin R.,Barros, David,Blacker, A. John,Heaney, Harry,Marples, Brian A.
, p. 6607 - 6613 (2006)
A range of substituted dihydroisoquinolinium salts has been tested in the catalytic asymmetric epoxidation of simple alkenes using our newly developed non-aqueous conditions employing tetraphenylphosphonium monoperoxysulfate (TPPP) as oxidant, giving ees of up to 97%.
N,N-Dialkylalloxans - a new class of catalyst for dioxirane epoxidations
Carnell, Andrew J.,Johnstone, Robert A. W.,Parsy, Christophe C.,Sanderson, William R.
, p. 8029 - 8032 (1999)
N,N-Dimethyl- and N,N-dibenzylalloxans 1a and 1b have been prepared and used as novel dioxirane catalysts for the epoxidation of a range of di- and tri-substituted alkenes in good to excellent yield. The dibenzylalloxan 1b can be recovered in high yield with no evidence of catalyst decomposition.
Highly efficient catalysts for epoxidation mediated by iminium salts
Bulman Page, Philip C.,Buckley, Benjamin R.,Appleby, Louise F.,Alsters, Paul A.
, p. 3405 - 3411 (2005)
A range of substituted dihydroisoquinolinium salts has been tested in the catalytic epoxidation of several alkenes. Catalyst loadings as low as 0.5 mol% have been used in the epoxidation of 1-phenylcyclohexene. Georg Thieme Verlag Stuttgart.
First Epoxidation Reaction of Carbonyl Compounds via Ferrocenyl Sulfur Ylides
Miniere, Stephanie,Reboul, Vincent,Arrayas, Ramon Gomez,Metzner, Patrick,Carretero, Juan Carlos
, p. 2249 - 2254 (2003)
Epoxidation reactions of carbonyl compounds (aldehydes and a ketone) mediated by sulfanyl ferrocenes have been successfully achieved in a one-pot reaction, under mild conditions. This reaction implies intermediary formation of a sulfonium salt (a ferrocenyl one was observed for the first time by 1H NMR) and then an ylide. The diastereoselectivity of the formation of stilbene oxide was unusual: the effect of steric hindrance and aromatic nature of the sulfide substituents have been evidenced. A catalytic asymmetric example with a planar chiral ferrocene is described.
A biomimetic iron catalyst for the epoxidation of olefins with molecular oxygen at room temperature
Schroeder, Kristin,Join, Benoet,Amali, Arlin Jose,Junge, Kathrin,Ribas, Xavi,Costas, Miquel,Beller, Matthias
, p. 1425 - 1429 (2011)
It's no sacrifice: A bio-inspired iron system, in which a β-keto ester serves as a sacrificial cosubstrate, readily epoxidizes olefins under ambient conditions with air. Aromatic olefins are oxidized in high yields with excellent chemoselectivity. Mechanistic investigations point out substantial differences to well-known radical-based autoxidations.
Pyrrolidine-Derived Iminium Salts as Catalysts for Alkene Epoxidation by Oxone
Armstrong, Alan,Ahmed, Ghafoor,Garnett, Ian,Goacolou, Katell
, p. 1075 - 1076 (1997)
Iminium triflate salts derived from pyrrolidine and aromatic aldehydes catalyse alkene epoxidation by Oxone. Catalysts 3d and 3e, with ortho-electron withdrawing substituents, are most effective.
