Elsevier, Tetrahedron, 2(58), p. 239-243
DOI: 10.1016/s0040-4020(01)01144-9
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Epoxidation of olefins by tert-butyl hydroperoxide (TBHP) was effectively catalyzed by a cubic silicon–titanium μ-oxo-complex, which is obtained from a bulky silanetriol and titanium alkoxides. The stoichiometric reaction of the complex with TBHP in the absence of olefin formed a novel complex as white solid. The comparison of this product with analogous complexes in 1H and 13C NMR spectra indicated that the titanium tert-butylperoxo complex; this kind of intermediate is considered to be active for epoxidation in titanium-based catalysts, was first isolated. This titanium peroxo complex reacted with cyclohexene to produce cyclohexene oxide without additional oxidant accompanying the formation of titanium tert-butoxide. All pathways of the catalytic cycle of the epoxidation using titanium catalysts were verified experimentally.