22520-40-7Relevant academic research and scientific papers
Olefin-dependent discrimination between two nonheme HO-Fev=O tautomeric species in catalytic H2O2 epoxidations
Company, Anna,Feng, Yan,Gueell, Mireia,Ribas, Xavi,Luis, Josep M.,Que Jr., Lawrence,Costas, Miquel
supporting information; experimental part, p. 3359 - 3362 (2009/12/06)
A study was conducted to demonstrate olefin-dependent discrimination of two nonheme HO-Fev=O tautomeric species in catalytic H2O 2 epoxidations. Mechanistic studies were carried out under the condition of excess of olefin to minimize over-oxidation reactions and all reactions for the study were carried out under a N2 atmosphere to prevent auto-oxidation process due to presence of O2. It was observed that the diol/epoxide (D/E) ration for these reaction was dependent on the specific olefin and ranged from 3/2 (cyclooctene) to 6/1 (1-octene). The oxidation of cyclooctene using H218O2 revealed that only 28% of the oxygen atoms in the epoxide derived from H 2O2. Mechanistic results suggested that HO-Fe v=O oxidant need to be labeled before its reaction with substrates.
Non-heme iron complexes for stereoselective oxidation: Tuning of the selectivity in dihydroxylation using different solvents
Klopstra, Marten,Roelfes, Gerard,Hage, Ronald,Kellogg, Richard M.,Feringa, Ben L.
, p. 846 - 856 (2007/10/03)
A new class of functional models for non-heme iron-based dioxygenases, including [(N3Py-Me)Fe(CH3CN)2](ClO4) 2 and [(N3Py-Bn)Fe(CH3CN)2](ClO 4)2 {N3Py-Me = [di(2-pyridyl)methyl]methyl(2-pyridyl) methylamine; N3Py-Bn = [di(2-pyridyl)methyl]benzyl(2-pyridyl)methylamine}, is presented here. NMR, UV and X-ray analyses revealed that six-coordinate low-spin FeII complexes with the pyridine N-atoms and the tertiary amine functionality of the ligand bound to Fe are formed. The two remaining coordination sites located cis to each other are occupied by labile CH 3CN groups that are easily exchanged by other ligands. We demonstrate that the reactivity and stereoselectivity of the complexes investigated depend on the choice of the solvent. The complexes have been examined as catalysts for the oxidation of both alkanes and olefins in CH3CN. In this solvent alkanes are oxidized to alcohols and ketones and olefins to the corresponding cis-epoxides and cis-diols. In acetone as solvent a different reactivity pattern was found, with, as the most striking example, the trans-dihydroxylation of cis-olefins. 18O-labeling studies in CH3CN establish incorporation of 18O from H218O2 and H218O in both the epoxide and the diol implicating an HO-FeV=18O active intermediate originating from an H 218O-FeIIIOOH species. These results are in full agreement with mechanistic schemes derived for other dioxygenase model systems. Based on labeling studies in acetone an additional oxidation mechanism is proposed for this solvent, in which the solvent acetone is involved. This is the first example of a catalyst that can give cis- or trans-dihydroxylation products, just by changing the solvent. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Diastereoselective reduction of acyclic hydroxyketones and diketones with an indium hydride reagent
Yamada, Masafumi,Horie, Tomoaki,Kawai, Masao,Yamamura, Hatsuo,Araki, Shuki
, p. 15685 - 15690 (2007/10/03)
Hydroxyketones and diketones have been reduced with lithium indium hydride to give meso-diols selectively. α-Hydroxyketones and α-diketones are reduced to meso-1,2-diols with high diastereoselectivities, whereas the selectivities of β-hydroxyketones and β-diketones are less satisfactory.
PHOTOCHEMICAL REACTION OF ALCOHOLS-I IRRADIATION OF ALIPHATIC ALCOHOLS
Balsells, R. Erra,Frasca, A. R.
, p. 245 - 255 (2007/10/02)
The UV irradiation of aliphatic alcohols gave α-glycols as the principal products.The values of the dl-α-glycol to meso-α-glycol ratios obtained in each example were analyzed.The stereochemical course of the formation of α-glycols, their conformations and configurations were established on basis of 1H NMR data.
