18479-57-7Relevant articles and documents
Highly efficient, regioselective, and stereospecific oxidation of aliphatic C-H groups with H2O2, catalyzed by aminopyridine manganese complexes
Ottenbacher, Roman V.,Samsonenko, Denis G.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
, p. 4310 - 4313 (2012)
Aminopyridine manganese complexes [LMnII(OTf)2] having a similar coordination topology catalyze the oxidation of unactivated aliphatic C-H groups with H2O2, demonstrating excellent efficiency (up to TON = 970), site selectivity, and stereospecificity (up to >99%).
Reductive ethylation of homoallyl alcohols with a disubstituted double bond with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide
Kulinkovich,Shevchuk,Isakov,Prokhorevich
, p. 659 - 664 (2006)
Homoallyl and bishomoallyl alcohols with a disubstituted double bond treated with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide are converted into the products of a reductive ethylation of the olefin fragment. Under similar conditions esters of β,γ-unsaturated carboxylic acids undergo a successive cyclopropanation of the ester group and reductive ethylation of the double carbon-carbon bond and yield 1-(3-ethylalkyl)cyclopropanols. The features of the observed reactions are explained in the framework of the carbometallation mechanism of the double carbon-carbon bond by the action of dialkoxytitanacyclopropane reagents. Pleiades Publishing, Inc. 2006.
Highly enantiospecific oxyfunctionalization of nonactivated hydrocarbon sites by perfluoro-cis-2-n-butyl-3-n-propyloxaziridine
Arnone, Alberto,Foletto, Stefania,Metrangolo, Pierangelo,Pregnolato, Massimo,Resnati, Giuseppe
, p. 281 - 284 (1999)
(equation presented) Nonactivated hydrocarbon sites of enantiopure compounds are oxyfunclionalized enantiospecifically by perfluoro-cis-2-n-butyl-3-n-propyloxaziridine under remarkably mild reaction conditions. The reaction occurs with retention of configuration at the oxidized stereogenic center, and the enantiospecificity is highly independent from both the carbon framework of the substrate and the presence of functional groups.
One-pot synthesis of aldoximes from alkenes: Via Rh-catalysed hydroformylation in an aqueous solvent system
Gr?ger, H.,Guntermann, A.,Hinzmann, A.,Jolmes, T.,Panke, D.,Plass, C.,R?sler, J.,Seidensticker, T.,Terhorst, M.,Vogt, D.,Vorholt, A. J.
supporting information, p. 7974 - 7982 (2020/11/30)
Aldoxime synthesis directly starting from alkenes was successfully achieved through the combination of hydroformylation and subsequent condensation of the aldehyde intermediate with aqueous hydroxylamine in a one-pot process. The metal complex Rh(acac)(CO)2 and the water-soluble ligand sulfoxantphos were used as the catalyst system, providing high regioselectivities in the initial hydroformylation. A mixture of water and 1-butanol was used as an environmentally benign solvent system, ensuring sufficient contact of the aqueous catalyst phase and the organic substrate phase. The reaction conditions were systematically optimised by Design of Experiments (DoE) using 1-octene as a model substrate. A yield of 85% of the desired linear, terminal aldoxime ((E/Z)-nonanal oxime) at 95% regioselectivity was achieved. Other terminal alkenes were also converted successfully under the optimised conditions to the corresponding linear aldoximes, including renewable substrates. Differences of the reaction rate have been investigated by recording the gas consumption, whereby turnover frequencies (TOFs) >2000 h-1 were observed for 4-vinylcyclohexene and styrene, respectively. The high potential of aldoximes as platform intermediates was shown by their subsequent transformation into the corresponding linear nitriles using aldoxime dehydratases as biocatalysts. The overall reaction sequence thus allows for a straightforward synthesis of linear nitriles from alkenes with water being the only by-product, which formally represents an anti-Markovnikov hydrocyanation of readily available 1-alkenes.
SYNTHESIS OF TETRAHYDROMYRCENOL
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Page/Page column 6, (2014/06/23)
The present invention relates to a new and improved synthesis of tetrahydromyrcenol (IUPAC name: 2,6-dimethyl-2-octanol).
Regioselective oxidation of nonactivated alkyl C-H groups using highly structured non-heme iron catalysts
Gómez, Laura,Canta, Merceì,Font, David,Prat, Irene,Ribas, Xavi,Costas, Miquel
, p. 1421 - 1433 (2013/03/29)
Selective oxidation of alkyl C-H groups constitutes one of the highest challenges in organic synthesis. In this work, we show that mononuclear iron coordination complexes Λ-[Fe(CF3SO3) 2((S,S,R)-MCPP)] (Λ-1P), Δ-[Fe(CF3SO 3)2((R,R,R)-MCPP)] (Δ-1P), Λ-[Fe(CF 3SO3)2((S,S,R)-BPBPP)] (Λ-2P), and Δ-[Fe(CF3SO3)2((R,R,R)-BPBPP)] (Δ-2P) catalyze the fast, efficient, and selective oxidation of nonactivated alkyl C-H groups employing H2O2 as terminal oxidant. These complexes are based on tetradentate N-based ligands and contain iron centers embedded in highly structured coordination sites defined by two bulky 4,5-pinenopyridine donor ligands, a chiral diamine ligand backbone, and chirality at the metal (Λ or Δ). X-ray diffraction analysis shows that in Λ-1P and Λ-2P the pinene rings create cavity-like structures that isolate the iron site. The efficiency and regioselectivity in catalytic C-H oxidation reactions of these structurally rich complexes has been compared with those of Λ-[Fe(CF3SO3) 2((S,S)-MCP)] (Λ-1), Λ-[Fe(CF3SO 3)2((S,S)-BPBP)] (Λ-2), Δ-[Fe(CF 3SO3)2((R,R)-BPBP)] (Δ-2), Λ-[Fe(CH3CN)2((S,S)-BPBP)](SbF6) 2 (Λ-2SbF6), and Δ-[Fe(CH3CN) 2((R,R)-BPBP)](SbF6)2 (Δ-2SbF 6), which lack the steric bulk introduced by the pinene rings. Cavity-containing complexes Λ-1P and Λ-2P exhibit enhanced activity in comparison with Δ-1P, Δ-2P, Λ-1, Λ-2, and Λ-2SbF6. The regioselectivity exhibited by catalysts Λ-1P, Λ-2P, Δ-1P, and Δ-2P in the C-H oxidation of simple organic molecules can be predicted on the basis of the innate properties of the distinct C-H groups of the substrate. However, in specific complex organic molecules where oxidation of multiple C-H sites is competitive, the highly elaborate structure of the catalysts allows modulation of C-H regioselectivity between the oxidation of tertiary and secondary C-H groups and also among multiple methylene sites, providing oxidation products in synthetically valuable yields. These selectivities complement those accomplished with structurally simpler oxidants, including non-heme iron catalysts Λ-2 and Λ-2SbF6.
An iron catalyst for oxidation of alkyl C-H bonds showing enhanced selectivity for methylenic sites
Prat, Irene,Gomez, Laura,Canta, Merce,Ribas, Xavi,Costas, Miquel
supporting information, p. 1908 - 1913 (2013/03/14)
Many are called but few are chosen: A nonheme iron complex catalyzes the oxidation of alkyl C-H bonds by using H2O2 as the oxidant, showing an enhanced selectivity for secondary over tertiary C-H bonds (see scheme). Copyright
An iron(III)-monoamidate complex catalyst for selective hydroxylation of alkane C-H bonds with hydrogen peroxide
Hitomi, Yutaka,Arakawa, Kengo,Funabiki, Takuzo,Kodera, Masahito
supporting information; experimental part, p. 3448 - 3452 (2012/06/16)
Selective oxidation: The success of the title reaction (see scheme) is caused by the strong electron donation from the amidate moiety of the dpaq ligand to the iron center (dpaq=2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8- yl-acetamidate). This process facilitates the O-O bond heterolysis of the intermediate FeIIIOOH species to generate a selective oxidant without forming highly reactive hydroxyl radicals. Copyright
Transition-metal-catalyzed cyclopropanation of nonactivated alkenes in dibromomethane with triisobutylaluminum
Brunner, Gerhard,Elmer, Susanne,Schroeder, Fridtjof
supporting information; experimental part, p. 4623 - 4633 (2011/10/09)
The cyclopropanation of nonactivated alkenes with inexpensive triisobutylaluminum (TIBA), in dibromomethane as solvent and reagent, is efficiently catalyzed by FeCl3 at ambient temperature. Catalytic amounts of CuI salts, CpTiCl3, and [CpFe(CO) 2]2 are similarly effective. 2-Methylpropane, generated after quench of excess TIBA can be trapped, and excess dibromomethane can be recycled, which makes the method industrially applicable. Solvent-free DIBAH or TIBA reduction of unsaturated carbonyl compounds, followed by in situ TIBA cyclopropanation of the unsaturated aluminum alcoholates in dibromomethane give cyclopropyl alkanols. Dienols such as geraniol, linalool or nor-radjanol are selectively cyclopropanated in their distal position, which allows the synthesis of flavor and fragrance compounds such as δ-citral, cis-javanol, and 7-methyl-georgywood. Uncontrollable exothermic events are avoided due to relatively low reaction temperatures made possible by the catalysts and by the addition mode of the reagents.[1]
Selective Aliphatic C-H Oxidation
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Page/Page column 14-15, (2011/02/18)
A composition including a complex of a metal, a tetradentate ligand, at least one ancillary ligand, and a counterion may be used for selective sp3 C—H bond oxidation. The tetradentate ligand may include a N-heterocyclic-N,N′-bis(pyridyl)-ethane-1,2-diamine group or a N,N′-bis(heterocyclic)-N,N′-bis(pyridyl)-ethane-1,2-diamine group. The composition can be used in combination with H2O2 to effect highly selective oxidations of unactivated sp3 C—H bonds over a broad range of substrates. The site of oxidation can be predicted, based on the electronic and/or steric environment of the C—H bond. In addition, the oxidation reaction does not require the presence of directing groups in the substrate.
