Manganese(II)/Picolinic Acid Catalyst System for Epoxidation of Olefins
An in situ generated catalyst system based on Mn(CF3SO3)2, picolinic acid, and peracetic acid converts an extensive scope of olefins to their epoxides at 0 °C in 5 min, with remarkable oxidant efficiency and no evidence of radical behavior. Competition experiments indicate an electrophilic active oxidant, proposed to be a high-valent Mn = O species. Ligand exploration suggests a general ligand sphere motif contributes to effective oxidation. The method is underscored by its simplicity and use of inexpensive reagents to quickly access high value-added products.
Moretti, Ross A.,Du Bois,Stack, T. Daniel P.
supporting information
p. 2528 - 2531
(2016/07/06)
Convenient method for epoxidation of alkenes using aqueous hydrogen peroxide
(Chemical Equation Presented) The complex [Ru(tpy)(pydic)] (1a) is an active catalyst for epoxidation of alkenes by aqueous 30% hydrogen peroxide in tertiary alcohols. The protocol is simple to operate and gives the corresponding epoxides in good to excellent yields. Chiral enantiopure [Ru(tpy*)(pydic) ] complexes have been synthesized and successfully applied in this procedure.
Man, Kin Tse,Klawonn, Markus,Bhor, Santosh,Doebler, Christian,Anilkumar, Gopinathan,Hugl, Herbert,Maegerlein, Wolfgang,Beller, Matthias
p. 987 - 990
(2007/10/03)
Epoxidation of olefins at low temperature using m-chloroperbenzoic acid
Epoxidation of olefins using m-chloroperbenzoic acid in dichloromethane without catalyst at low temperature is described.
Srinivasan,Chandrasekharam,Vani,Chida, A. Seema,Singh
p. 1853 - 1858
(2007/10/03)
Efficient epoxidation of alkenes with aqueous hydrogen peroxide catalyzed by methyltrioxorhenium and 3-cyanopyridine
The epoxidation of alkenes with 30% aqueous hydrogen peroxide is catalyzed efficiently by methyltrioxorhenium (MTO) in the presence of pyridine additives. The addition of 1-10 mol % of 3-cyanopyridine increases the system's efficiency for terminal and trans-disubstituted alkenes resulting in high isolated yields of the corresponding epoxides. The system allows for epoxidation of alkenes with various functional groups. Alkenes leading to acid-sensitive products are efficiently epoxidized using a mixture of pyridine and 3-cyanopyridine as additives. This method is operationally very simple and uses an environmentally benign oxidant. The effects of different pyridine additives on the alkene conversion and the catalyst lifetime are discussed.
Adolfsson,Coperet,Chiang,Yudin
p. 8651 - 8658
(2007/10/03)
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