- Selective transition-metal-free vicinal cis-dihydroxylation of saturated hydrocarbons
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A transition-metal-free cis-dihydroxylation of saturated hydrocarbons under ambient reaction conditions has been developed. The described approach allows a direct and selective synthesis of vicinal diols. The new reaction thereby proceeds via radical iodination and a sequence of oxidation steps. A broad scope of one-pot dual C(sp3)-H bond functionalization for the selective synthesis of vicinal syn-diols was demonstrated.
- Bering, Luis,Antonchick, Andrey P.
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p. 452 - 457
(2016/12/30)
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- L-Proline-derived ligands to mimic the '2-His-1-carboxylate' triad of the non-haem iron oxidase active site
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Non-haem iron(II) oxidases (NHIOs) catalyse a variety of oxidative transformations in biology. The iron-binding environment of the NHIO active site typically incorporates a '2-His-1-carboxylate' facial triad of amino acid side-chains, a motif that has emerged as a defining feature of the enzyme family. Towards the goal of biomimetic, iron-mediated C-H activation we have synthesized a series of peptidomimetic ligands from l-proline. By coupling l-proline to 2,6-bis(bromomethyl)pyridine, 2-(bromomethyl)-6-((tert- butyldimethylsilyloxy)methyl)pyridine and picolinic acid, we have generated several new ligand architectures designed to complex with iron(II) and mimic the NHIO active site. The resulting iron complexes promote modest levels of alkene dihydroxylation and allylic oxidation using hydrogen peroxide as oxidant.
- Dungan, Victoria J.,Wong, Shwo Mun,Barry, Sarah M.,Rutledge, Peter J.
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experimental part
p. 3231 - 3236
(2012/06/01)
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- Regioselective epoxidation of different types of double bonds over large-pore titanium silicate Ti-β
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Regioselective epoxidation of different types of double bonds located within the cyclic and acyclic parts of bulky olefins has been investigated using large-pore titanium silicate Ti-β in the presence of dilute aqueous H 2O2 as oxidant under mild liquid-phase conditions. Our experimental results revealed that side-chain vinylic double bonds are selectively epoxidized than those in the cyclohexene-ring. The epoxidation tendency of various bulky olefins with different positional and/or geometric isomers over Ti-β follows the order: terminal -CC- > ring -CC- ≈ bicyclic ring -CC- > allylic C - H bond. Unlike 4-vinyl-1-cyclohexene, epoxidation of an equimolar mixture of cyclohexene and 1-hexene under identical conditions using Ti-β exhibits completely different selectivity and product distributions. Steric factor and accessibility of reactants to active Ti-sites are responsible for the observed regioselectivity of bulky alkenes.
- Sasidharan, Manickam,Bhaumik, Asim
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experimental part
p. 60 - 67
(2010/12/18)
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- A new process for preparing dialdehydes by catalytic oxidation of cyclic olefins with aqueous hydrogen peroxide
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Dialdehydes were prepared by the reaction between cyclic olefins and aqueous hydrogen peroxide catalyzed by tungstic acid. Glutaraldehyde and adipaldehyde were synthesized by this method with good yield. Several different conditions were tested.
- Deng,Xu,Chen,Jiang
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p. 3503 - 3514
(2007/10/02)
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- REGIOSELECTIVE TITANIUM MEDIATED REDUCTIVE OPENING OF 2,3-EPOXY ALCOHOLS
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Lithium borohydride reduction of 2,3-epoxy alcohols was shown to yield 1,2-diols in high regioselectivity with the aid of titanium tetraisopropoxide in benzene solution.
- Dai, Li-xin,Lou, Bo-liang,Zhang, Ying-zhi,Guo, Guang-zhong
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p. 4343 - 4346
(2007/10/02)
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- REGIO- AND STEREOSELECTIVE RING OPENING OF EPOXY ALCOHOLS WITH ORGANOALUMINIUM COMPOUNDS LEADING TO 1,2-DIOLS
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Introduction of alkyl, alkynyl group, or hydride occurs regioselectively at the 3 position of the epoxy alcohols with inversion of the configuration upon treatment with organoaluminium reagents to produce vic-diols.
- Suzuki, Toshifumi,Saimoto, Hiroyuki,Tomioka, Hiroki,Oshima, Koichiro,Nozaki, Hitosi
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p. 3597 - 3600
(2007/10/02)
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