81887-55-0Relevant academic research and scientific papers
Organocatalytic epoxidation and allylic oxidation of alkenes by molecular oxygen
Orfanidou, Maria,Petsi, Marina,Zografos, Alexandros L.
supporting information, p. 9172 - 9178 (2021/11/30)
Pyrrole-proline diketopiperazine (DKP) acts as an efficient mediator for the reduction of dioxygen by Hantzsch ester under mild conditions to allow the aerobic metal-free epoxidation of electron-rich alkenes. Mechanistic crossovers are underlined, explaining the dual role of Hantzsch ester as a reductant/promoter of the DKP catalyst and a simultaneous competitor for the epoxidation of alkenes when HFIP is used as a solvent. Expansion of this protocol to the synthesis of allylic alcohols was achieved by adding a catalytic amount of selenium dioxide as an additive, revealing a superior method to the classical application of t-BuOOH as a selenium dioxide oxidant.
Epoxidation of strained alkenes catalysed by (1,2-dimethyl-4(1H)pyridinone-3-olate)2MnIIICl
Robinson-Miller, Adam P.,Wyatt, Mark F.,Tétard, David
, p. 376 - 390 (2015/01/30)
The mild epoxidation of strained alkenes using (DMPO)2MnCl catalyst (DMPO = 1,2-dimethyl-4(1H)-pyridinone-3-olate) in the presence of various oxidants was studied. Hydrogen peroxide and monopersulfate were found to be the best oxidants when used with imidazole in acetonitrile at 4 °C, with up to 94% conversion. Dismutation of hydrogen peroxide was also observed when used as an oxidant. The epoxidation using hydrogen peroxide or monoperoxysulfate appears to be mild and very selective for strained alkenes. A mechanism is proposed where imidazole is required for activation of the oxidant and where a detected MnV = O species is proposed as the active species. Competitive reaction between H2O2 and the substrate for the active species is proposed and homolytic vs heterolytic scissions of the OO bond of the oxidant are discussed.
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 (2007/10/03)
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.
Ring size effect in oxidation of 1-phenylcycloalkenes with chromic anhydride-pyridine complex: Preferential formation of epoxide with increase in ring size
Singh, Chandan,Saxena, Gunjan
, p. 1176 - 1177 (2007/10/02)
A marked ring size effect in the oxidation of 1-phenylcycloalkenes (1) with chromic anhydride-pyridine complex has been observed.While 1-phenylcyclopentene (1a) and 1-phenylcyclohexene (1b) give the expected α,β-unsaturated cyclic ketones (2a,b) 1-phenylcycloheptene (1c) and 1-phenylcyclooctene (1d) furnish epoxides (5c,d) as the major products.
AUTOOXIDATION OF ARYLCYCLOALKENES: A METHOD FOR THE PREPARATION OF EPOXIDES
Sethi, Shanti C.,Natu, Arun D.,Wadia, Murzban S.
, p. 221 - 228 (2007/10/02)
A method for the preparation of arylcycloalkene epoxides has been developed via the autooxidation of the corresponding arylcycloalkenes.
