Vanadium-catalyzed epoxidation of cyclic allylic alcohols. Stereoselectivity and stereocontrol mechanism

Itoh, Takashi; Jitsukawa, Koichiro; Kaneda, Kiyotomi; Teranishi, Shiichirō

doi:10.1021/ja00495a027

Cited by 258 publications

(112 citation statements)

References 12 publications

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“…By using proline-derived hydroxamic acids as chiral ligands, even higher enantioselectivities (up to 80% enantiomeric excess) could be achieved [12,17]. Furthermore, the VO(acac) 2 /TBHP/ligand system allows the highly chemoselective mono-epoxidation of olefinic alcohols like geraniol [18,19], as unfunctionalized alkenes react more slowly with this system. The active species have been identified in stoichiometric reactions as mononuclear oxoperoxovanadium(V) complexes, of which some have been structurally characterized [20].…”

Section: Introductionmentioning

confidence: 99%

Mechanistic insight into the cyclohexene epoxidation with VO(acac)2 and tert-butyl hydroperoxide

Vandichel

Leus

Voort

et al. 2012

Journal of Catalysis

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The epoxidation reaction of cyclohexene is investigated for the system vanadyl acetylacetonate (VO(acac) 2 ) as catalyst with tert-butyl hydroperoxide (TBHP) as oxidant with the aim to identify the most active species for epoxidation and to retrieve insight into the most plausible epoxidation mechanism. The reaction mixture is composed of various inactive and active complexes in which vanadium may either have oxidation state +IV or +V. Inactive species are activated with TBHP to form active complexes. After reaction with cyclohexene each active species transforms back into an inactive complex which may be reactivated again. The reaction mixture is quite complex containing hydroxyl, acetyl acetonate, acetate or a tert-butoxide anion as ligands and thus various ligand exchange reactions may occur among active and inactive complexes. Also radical decomposition reaction allow transforming V +IV to V +V species. To obtain insight into the most abundant active complexes, each of previous transformation steps has been modeled through thermodynamic equilibrium steps. To unravel the nature of the most plausible epoxidation mechanism, first principle chemical kinetics calculations have been performed on all proposed epoxidation pathways. Our results allow to conclude that the concerted Sharpless mechanism is the preferred reaction mechanism and that alkylperoxo species V +IV O(L)(OOtBu) and V +V O(L 1 )(L 2 )(OOtBu) species are most abundant. At the onset of the catalytic cycle vanadium +IV species may play an active role but as the reaction proceeds, reaction mechanisms that involve vanadium +V species are preferred as the acetyl acetonate is readily oxidized. Additionally an experimental IR and kinetic study has been performed to give a qualitative composition of the reaction mixture and to obtain experimental kinetic data for comparison with our theoretical values. The agreement between theory and experiment is satisfactory.

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Section: Introductionmentioning

confidence: 99%

Mechanistic insight into the cyclohexene epoxidation with VO(acac)2 and tert-butyl hydroperoxide

Vandichel

Leus

Voort

et al. 2012

Journal of Catalysis

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“…V IV O(acac) 2 was first prepared in 1876 [21] and since then it has been known as a precursor for the synthesis of V complexes [22] and as a catalyst for epoxidations, namely selective epoxidation of allylic alcohols [23,24,25]. V IV O(acac) 2 was found to have insulin-enhancing activity, with apparent low toxicity [9,26], and it is thus considered as a potential therapeutic agent for diabetes mellitus [27].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

DNA cleavage activity of VIVO(acac)2 and derivatives

Butenko

Tomaz

Nouri

et al. 2009

Journal of Inorganic Biochemistry

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“…The 1,2-reduction of cyclopentenone 10 with lithium aluminun hydride gave cyclopentenol 11. Stereoselective epoxidation 6) of cyclopentenol 11 C-NMR spectra. Figure 3 shows the concentration-inhibition curves of benzyl ethers (1-8) against the first sheath growth of barnyardgrass.…”

Section: Evaluation Of Herbicidal Activitymentioning

confidence: 99%

Synthesis and Herbicidal Activities of the 0-Syn and 0-Anti Benzyl Epoxycyclopentyl Ethers

2004

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Vanadium-catalyzed epoxidation of cyclic allylic alcohols. Stereoselectivity and stereocontrol mechanism

Cited by 258 publications

References 12 publications

Mechanistic insight into the cyclohexene epoxidation with VO(acac)2 and tert-butyl hydroperoxide

Mechanistic insight into the cyclohexene epoxidation with VO(acac)2 and tert-butyl hydroperoxide

DNA cleavage activity of VIVO(acac)2 and derivatives

Synthesis and Herbicidal Activities of the 0-Syn and 0-Anti Benzyl Epoxycyclopentyl Ethers

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