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Highly Selective Epoxidation of Cycloaliphatic Alkenes with Aqueous Hydrogen Peroxide Catalyzed by [PO 4 {WO(O 2 ) 2 } 4 ] 3− /Imidazole
Author(s) -
Kamata Keigo,
Sugahara Kosei,
Ishimoto Ryo,
Nojima Susumu,
Okazaki Motoya,
Matsumoto Takaya,
Mizuno Noritaka
Publication year - 2014
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201402268
Subject(s) - imidazole , catalysis , hydrogen peroxide , chemistry , epoxide , aqueous solution , selectivity , lewis acids and bases , stoichiometry , peroxide , polymer chemistry , organic chemistry
Abstract In the presence of imidazole as an additive, a phosphorus‐containing tetranuclear peroxotungstate, THA 3 [PO 4 {WO(O 2 ) 2 } 4 ] ( I , THA=tetra‐ n ‐hexylammonium), could act as an efficient catalyst for epoxidation of cycloaliphatic alkenes with 30 % aqueous hydrogen peroxide (H 2 O 2 ). Compound I showed higher catalytic activity and selectivity to epoxide than other tungstates. By using the I /imidazole system, various kinds of cycloaliphatic alkenes could be highly selectively converted into the acid‐sensitive epoxides including industrially important diepoxides in high to excellent yields under the almost stoichiometric conditions. The 1 H NMR spectroscopy showed that imidazole would work not only as a proton acceptor but also as a Lewis base to remarkably suppress the acid‐catalyzed ring opening of epoxides.