608-69-5Relevant academic research and scientific papers
Selective Monoacylation of Diols and Asymmetric Desymmetrization of Dialkyl meso-Tartrates Using 2-Pyridyl Esters as Acylating Agents and Metal Carboxylates as Catalysts
Hashimoto, Yuki,Michimuko, Chiaki,Yamaguchi, Koki,Nakajima, Makoto,Sugiura, Masaharu
, p. 9313 - 9321 (2019/08/12)
With 2-pyridyl benzoates as acylating agents and Zn(OAc)2 as a catalyst, 1,2-diols, 1,3-diols, and catechol were selectively monoacylated. Furthermore, the highly enantioselective desymmetrization of meso-tartrates was achieved for the first time, utilizing 2-pyridyl esters and NiBr2/AgOPiv/Ph-BOX in CH3CN or CuCl2/AgOPiv/Ph-BOX in EtOAc catalyst systems (up to 96% ee). The latter catalyst system was also effective for the kinetic resolution of dibenzyl dl-tartrate.
Mechanistically Driven Development of an Iron Catalyst for Selective Syn-Dihydroxylation of Alkenes with Aqueous Hydrogen Peroxide
Borrell, Margarida,Costas, Miquel
supporting information, p. 12821 - 12829 (2017/09/25)
Product release is the rate-determining step in the arene syn-dihydroxylation reaction taking place at Rieske oxygenase enzymes and is regarded as a difficult problem to be resolved in the design of iron catalysts for olefin syn-dihydroxylation with potential utility in organic synthesis. Toward this end, in this work a novel catalyst bearing a sterically encumbered tetradentate ligand based in the tpa (tpa = tris(2-methylpyridyl)amine) scaffold, [FeII(CF3SO3)2(5-tips3tpa)], 1 has been designed. The steric demand of the ligand was envisioned as a key element to support a high catalytic activity by isolating the metal center, preventing bimolecular decomposition paths and facilitating product release. In synergistic combination with a Lewis acid that helps sequestering the product, 1 provides good to excellent yields of diol products (up to 97% isolated yield), in short reaction times under mild experimental conditions using a slight excess (1.5 equiv) of aqueous hydrogen peroxide, from the oxidation of a broad range of olefins. Predictable site selective syn-dihydroxylation of diolefins is shown. The encumbered nature of the ligand also provides a unique tool that has been used in combination with isotopic analysis to define the nature of the active species and the mechanism of activation of H2O2. Furthermore, 1 is shown to be a competent synthetic tool for preparing O-labeled diols using water as oxygen source.
Cis-Dihydroxylation of electron deficient olefins catalysed by an oxo-bridged diiron(III) complex with H2O2
Kejriwal, Ambica,Biswas, Sachidulal,Biswas, Achintesh N.,Bandyopadhyay, Pinaki
, p. 77 - 84 (2016/01/09)
Room temperature oxidation of olefins catalysed by a symmetrical (μ-oxo)(μ-hydroxo)diiron(III) complex (1) based on the amino pyridyl ligand bpmen (bpmen = N,N′-dimethyl-N,N′-bis(2-pyridyl methyl)ethane-1,2-diamine) with hydrogen peroxide under the conditions of limiting substrate is described. Excellent substrate conversions have been achieved under ambient reaction conditions. The olefin oxidation efficacy of the 1/H2O2 system has been found to get improved in presence of acetic acid. The catalytic system has been shown to oxidise electron-deficient olefins to the corresponding cis-diols, while epoxidation is favoured in case of electron-rich olefins. The μ-oxo diiron(III) core of the catalyst 1 has been found be regenerated after the catalytic turnovers. Addition of a second batch of substrate and oxidant at the end of the olefin oxidation results in the formation of almost identical amounts of epoxides/diols. Moreover, the regenerated catalyst exhibits a significantly higher preference towards the oxidation of electron-deficient olefins.
Synthesis and the absolute configuration of both enantiomers of 4,5-dihydroxy-3-(formyl)cyclopent-2-enone acetonide as a new chiral building block for prostanoid synthesis
Lukasik, Beata,Mikolajczyk, Marian,Bujacz, Grzegorz,Zurawiski, Remigiusz
, p. 807 - 816 (2015/02/19)
The synthesis of both enantiomers of 4,5-dihydroxy-3-(formyl)cyclopent-2-enone acetonide (5) was accomplished in five steps starting from meso-tartaric acid (6). The key steps involved are preparation of the isopropylidene protected 3-[(dimethoxyphosphoryl)methyl]-4,5-dihydroxycyclopent-2-enone (9), resolution of the diastereoisomeric products 10 of the Horner reaction of racemic 9 with (R)-glyceraldehyde acetonide and the final regioselective ozonolysis of the exocyclic carbon-carbon double bond of the separated dienones 10 leading to both enantiomeric title compounds 5. The absolute configuration of both enantiomers was initially assigned based on the comparison of the chiroptical properties obtained from the DFT calculations with the experimental data and finally confirmed by X-ray analysis.
General and efficient α-oxygenation of carbonyl compounds by TEMPO induced by single-electron-transfer oxidation of their enolates
Dinca, Emanuela,Hartmann, Philip,Smrcek, Jakub,Dix, Ina,Jones, Peter G.,Jahn, Ullrich
supporting information, p. 4461 - 4482 (2012/10/30)
A generally applicable method for the synthesis of protected α-oxygenated carbonyl compounds is reported. It is based on the single-electron-transfer oxidation of easily generated enolates to the corresponding α-carbonyl radicals. Coupling with the stable free radical TEMPO provides α-(piperidinyloxy) ketones, esters, amides, acids or nitriles in moderate-to-excellent yields. Enolate aggregates influence the outcome of the oxygenation reactions significantly. Competitive reactions have been analyzed and conditions for their minimization are presented. Chemoselective reduction of the products led to either N-O bond cleavage to α-hydroxy carbonyl compounds or reduction of the carbonyl functionality tomonoprotected 1,2-diols or O-protected amino alcohols. The oxygenation of enolates proves to be the most general and effective methodology for the synthesis of O-protected α-oxy carbonyl compounds and nitriles A. The scope and limitations of the electron-transfer-induced radical coupling reaction with TEMPO are presented. The reaction pathways are outlined. Methods for the deprotection to α-hydroxy carbonyl compounds B are provided and discussed. Copyright
Investigation of tartaric acid amide formation by thermolysis of tartaric acids with alkylamines
Gonzalez, Susana V.,Carlsen, Per
experimental part, p. 325 - 336 (2011/08/22)
N,N'-dialkyltartramides were obtained by conventional thermolysis at 200 °C without a solvent, of the L-, D- or meso-tartaric acids with butyl-, hexyl- and octylamine, respectively. The products proved in all cases to be mixtures of all the possible stereoisomers, in ratios that depended on the stereochemistry of the tartaric acid applied, retaining an excess of the configuration of the starting material. Isomerization of the initially formed diamide did not take place under the reaction conditions. Mechanistically the transformation was rationalized in terms of two competing pathways - the direct substitution of the alkylamine into the carboxylic acid group, - in competition with ketene formation and subsequent amide formation. As a method for stereoselective synthesis of optically active N,N'-dialkyltartramides, the method may be considered obsolete and of little practical value; however, it provided new insight into the mechanisms of amide formation. ARKAT-USA, Inc.
Olefin cis-dihydroxylation with bio-inspired iron catalysts. evidence for an FeII/FeIV catalytic cycle
Oldenburg, Paul D.,Feng, Yan,Pryjomska-Ray, Iweta,Ness, Daniel,Que Jr., Lawrence
experimental part, p. 17713 - 17723 (2011/03/17)
Iron(II) complexes of a series of N-acylated dipyridin-2-ylmethylamine ligands (R-DPAH) have been investigated as catalysts for the cis-dihydroxylation of olefins to model the action of Rieske dioxygenases that catalyze arene cis-dihydroxylation. The Rieske dioxygenases have a mononuclear iron active site coordinated to a 2-histidine-1-carboxylate facial triad motif. The R-DPAH ligands are designed to provide a facial N,N,O-ligand set that mimics the enzyme active site. The iron(II) complexes of the R-DPAH ligands activate H 2O2 to effect the oxidation of olefin substrates into cis-diol products. As much as 90% of the H2O2 oxidant is converted into cis-diol, but a large excess of olefin is required to achieve the high conversion efficiency. Reactivity and mechanistic comparisons with the previously characterized Fe(TPA)/H2O2 catalyst/oxidant combination (TPA = tris(pyridin-2-ylmethyl)amine) lead us to postulate an FeII/FeIV redox cycle for the Fe(R-DPAH) catalysts in which an FeIV(OH)2 oxidant carries out the cis-hydroxylation of olefins. This hypothesis is supported by three sets of observations: (a) the absence of a lag phase in the conversion of the H 2O2 oxidant into a cis-diol product, thereby excluding the prior oxidation of the Fe(II) catalyst to an Fe(III) derivative as established for the Fe(TPA) catalyst; (b) the incorporation of H218O into the cis-diol product, thereby requiring O-O bond cleavage to occur prior to cis-diol formation; and (c) the formation of cis-diol as the major product of cyclohexene oxidation, rather than the epoxide or allylic alcohol products more commonly observed in metal-catalyzed oxidations of cyclohexene, implicating an oxidant less prone to oxo transfer or H-atom abstraction.
Cis-dihydroxylation of alkenes with oxone catalyzed by iron complexes of a macrocyclic tetraaza ligand and reaction mechanism by ESI-MS spectrometry and DFT calculations
Chow, Toby Wai-Shan,Wong, Ella Lai-Ming,Guo, Zhen,Liu, Yungen,Huang, Jie-Sheng,Che, Chi-Ming
experimental part, p. 13229 - 13239 (2010/12/19)
[FeIII(L-N4Me2)Cl2]+ (1, L-N4Me2 = N,N′-dimethyl-2,11-diaza[3.3](2,6) pyridinophane) is an active catalyst for cis-dihydroxylation of various types of alkenes with oxone at room temperature using limiting amounts of alkene substrates. In the presence of 0.7 or 3.5 mol % of 1, reactions of electron-rich alkenes, including cyclooctene, styrenes, and linear alkenes, with oxone (2 equiv) for 5 min resulted in up to >99% substrate conversion and afforded cis-diol products in up to 67% yield, with cis-diol/epoxide molar ratio of up to 16.8:1. For electron-deficient alkenes including α,β-unsaturated esters and α,β-unsaturated ketones, their reactions with oxone (2 equiv) catalyzed by 1 (3.5 mol %) for 5 min afforded cis-diols in up to 99% yield with up to >99% substrate conversion. A large-scale cis-dihydroxylation of methyl cinnamate (9.7 g) with oxone (1 equiv) afforded the cis-diol product (8.4 g) in 84% yield with 85% substrate conversion. After catalysis, the L-N4Me2 ligand released due to demetalation can be reused to react with newly added Fe(ClO4)2?4H2O to generate an iron catalyst in situ, which could be used to restart the catalytic alkene cis-dihydroxylation. Mechanistic studies by ESI-MS, isotope labeling studies, and DFT calculations on the 1-catalyzed cis-dihydroxylation of dimethyl fumarate with oxone reveal possible involvement of cis-HO-Fe V O and/or cis-O FeV O species in the reaction; the cis-dihydroxylation reactions involving cis-HO-FeV O and cis-O FeV O species both proceed by a concerted but highly asynchronous mechanism, with that involving cis-HO-FeV O being more favorable due to a smaller activation barrier.
A structural and functional model for dioxygenases with a 2-His-1-carboxylate triad
Oldenburg, Paul D.,Ke, Chun-Yen,Tipton, A. Alex,Shteinman, Albert A.,Que Jr., Lawrence
, p. 7975 - 7978 (2007/10/03)
(Chemical Equation Presented) An attractive model: The iron complex shown on the left models the 2-His-1-carboxylate active sites of Rieske dioxygenases both in terms of structure and function. 18O-labeling studies of olefin dihydroxylation support the involvement of a high-valent iron-oxo species.
Supported ruthenium nanoparticle catalyst for cis -dihydroxylation and oxidative cleavage of alkenes
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Page/Page column 3; 5, (2008/06/13)
The present invention relates to the use of nanosized metal particles (e.g., ruthenium) grafted on inert solid support for oxidation of alkenes. The supported metal catalyst can effect cis-dihydroxylation and oxidative cleavage of alkenes to give the respective cis-diols and carbonyl products.
