17438-89-0Relevant articles and documents
Transfer of alk-1-enyl group from boron to aluminium: A novel way to prepare (E)-alk-1-enyldiisobutylalanes
Hoshi, Masayuki,Shirakawa, Kazuya
, p. 2146 - 2147 (2002)
Treatment of (E)-alk-1-enyldicyclohexylboranes 1 with diisobutylaluminium hydride (DIBAL-H) in the presence of hex-1-ene at room temperature results in transfer of the alk-1-enyl group from boron to aluminium to give (E)-alk-1-enyldiisobutylalanes 2 with retention of configuration at the double bond.
Blum,Kraus
, p. 227,237 (1971)
Effect of Silica Gel on the Benzenesulfinic Acid Catalyzed Isomerization of Vinylsilanes. Formation of Silyl Benzenesulfinate
Ochiai, Masahito,Takaoka, Yoshikazu,Ukita, Tatsuzo,Nagao, Yoshimitsu,Fujita, Eiichi
, p. 2346 - 2350 (1989)
A new method for the isomerization of (Z)-vinylsilanes into the E isomers has been developed.In contrast to the facile protodesilylation of vinylsilanes with arenesulfinic acids, use of silica gel as an additive in the reaction of vinylsilanes with benzenesulfinic acid makes possible the selective isomerization of the double-bond geometry by decreasing the rate of the competing protodesilylation.On the basis of the finding that the isomerization proceeds on the surface of the silica gel activated with benzenesulfinic acid and that benzenesulfinic esters such as ethyl, tributylstannyl, and trimethylsilyl benzenesulfinates are also effective as catalysts for the isomerization, the selective isomerization of vinylsilanes was interpreted in terms of the in situ formation of silyl benzenesulfinate bound to a silanol group of the surface of silica gel.
Improved preparation of an olefin metathesis catalyst bearing quaternary ammonium tag (FixCat) and its use in ethenolysis and macrocyclization reactions after immobilization on metal-organic framework (MOF)
Milewski, Mariusz,Kajetanowicz, Anna,Grela, Karol
, p. 73 - 84 (2020)
An optimized synthesis of a key intermediate Ru4 in substantially improved yield of 50% and in scale up to 1 gram was described. Such obtained Ru4 was quantitatively converted into useful quaternary ammonium tagged catalyst Ru1 (FixCat) and immobilized in a metal-organic framework (MOF). Next, two challenging applications, not studied previously with hybrid Ru1@MOF catalyst were attempted. In the case of the RCM reaction yielding a macrocyclic musk lactone, heterogeneous Ru1@MOF exhibited under high-dilution conditions high resistance towards unwanted C-C double bond migration, thus offering superior selectivity as compared to analogous homogeneous catalysts. In ethenolysis of ethyl oleate, Ru1@MOF exhibited only slightly better selectivity as compared to well-known general-purpose Hoveyda-Grubbs SIMes and SIPr catalysts, while it was not able to challenge the benchmark Bertrand-Hoveyda-Grubbs catalyst in this transformation.
A Gentler Touch: Synthesis of Modern Ruthenium Olefin Metathesis Catalysts Sustained by Mechanical Force
Mukherjee, Nirmalya,Marczyk, Anna,Szczepaniak, Grzegorz,Sytniczuk, Adrian,Kajetanowicz, Anna,Grela, Karol
, p. 5362 - 5369 (2019)
Mechanochemical synthesis of nine contemporary ruthenium catalysts used for olefin metathesis is described, being the first reported example of formation of Ru carbene organometallic complexes in solid state. Three key organometallic transformations commonly used in the synthesis of the second and third generations of Ru catalysts in solution—phosphine ligand (PCy3) exchange with in situ formed N-heterocyclic carbene (NHC) ligand, PCy3 to pyridine ligand replacement, and benzylidene ligands interchange—were proved to work under mechanochemical conditions, affording the targets in high purity. Mechanochemical approach not only requires less amounts of organic solvent (null for synthesis, only for purification) and is scalable, but also allows for transformations that were reported impossible in the solution phase.
Akiyama,Hooz
, p. 4115 (1973)
Synthesis of selenoxides by oxidation of selenides with superoxide radical anions and 2-nitrobenzenesulfonyl chloride
Tiecco, Marcello,Testaferri, Lorenzo,Temperini, Andrea,Terlizzi, Raffaella,Bagnoli, Luana,Marini, Francesca,Santi, Claudio
, p. 5165 - 5168 (2005)
Alkyl phenyl selenoxides were produced in excellent yields by oxidation of the corresponding selenides with 2-nitrobenzenesulfonyl chloride and potassium superoxide in dry acetonitrile at -15°C.
Direct and Tandem Routes for the Copolymerization of Ethylene with Polar Functionalized Internal Olefins
Chen, Min,Chen, Changle
, p. 1206 - 1210 (2020)
Transition metal catalyzed ethylene copolymerization with polar monomers is a highly challenging reaction. After decades of research, the scope of suitable comonomer substrates has expanded from special to fundamental polar monomers and, recently, to 1,1-disubstituted ethylenes. Described in this contribution is a direct and tandem strategy to realize ethylene copolymerization with various 1,2-disubstituted ethylenes. The direct route is sensitive to sterics of both the comonomers and the catalyst. In the tandem route, ruthenium-catalyzed ethenolysis can convert 1,2-disubstituted ethylenes into terminal olefins, which can be subsequently copolymerized with ethylene to afford polar functionalized polyolefins. The one-pot, two-step tandem route is highly versatile and efficient in dealing with challenging substrates. This work is a step forward in terms of expanding the substrate scope for transition metal catalyzed ethylene copolymerization with polar-functionalized comonomers.
A combined m?ssbauer, magnetic circular dichroism, and density functional theory approach for iron cross-coupling catalysis: Electronic structure, in situ formation, and reactivity of iron-mesityl-bisphosphines
Daifuku, Stephanie L.,Al-Afyouni, Malik H.,Snyder, Benjamin E. R.,Kneebone, Jared L.,Neidig, Michael L.
, p. 9132 - 9143 (2014)
While iron-bisphosphines have emerged as effective catalysts for C-C cross-coupling, the nature of the in situ formed iron species, elucidation of the active catalysts and the mechanisms of catalysis have remained elusive. A combination of 57Fe M?ssbauer and magnetic circular dichroism (MCD) spectroscopies of well-defined and in situ formed mesityl-iron(II)-SciOPP species combined with density functional theory (DFT) investigations provides the first direct insight into electronic structure, bonding and in situ speciation of mesityl-iron(II)-bisphosphines in the Kumada cross-coupling of MesMgBr and primary alkyl halides using FeCl2(SciOPP). Combined with freeze-trapped solution M?ssbauer studies of reactions with primary alkyl halides, these studies demonstrate that distorted square-planar FeMes 2(SciOPP) is the active catalyst for cross-coupling and provide insight into the molecular-level mechanism of catalysis. These studies also define the effects of key reaction protocol details, including the role of the slow Grignard addition method and the addition of excess SciOPP ligand, in leading to high product yields and selectivities.
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Labar,D. et al.
, p. 1141 - 1144 (1978)
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Degradation kinetics and solvent effects of various long-chain quaternary ammonium salts
Kleijwegt, Roel J. T.,Winkenwerder, Wyatt,Baan, Wim,van der Schaaf, John
, p. 16 - 27 (2021/08/30)
Surfactants such as quaternary ammonium salts (QAS) have been in increasing demand, for emerging new applications. Recent attempts at process intensification of their production have disclosed the need for a better understanding of QAS thermal stability. This work aims to determine the degradation kinetics of various QASs and the associated solvent?effects. The degradation kinetics of four methyl carbonate QASs were determined in various polar solvents in stainless steel batch autoclaves. (Formula presented.) H NMR spectrometry was employed for offline analysis of the reaction mixtures. The kinetic parameters were then used to compare the thermal stability of the four compounds in the polar solvents. Water showed no degradation, and methanol (MeOH) was the solvent that provided the second-best stability. Water–MeOH mixtures may provide an overall optimum. Moreover, and longer long-chain substituents increased the degradation?rate. Thermogravimetric analysis was used to obtain the thermal stability in a solid state, that is, solventless environment. Isoconversional analysis showed that no reliable kinetic parameters could be determined. Nevertheless, the data did allow for a comparison of the thermal stability of 14 different QASs. Furthermore, the relative instability of the compounds in the solid state demonstrated the challenges of solventless QAS?production.
ACYCLIC CARBENE LIGAND FOR RUTHENIUM COMPLEX FORMATION, RUTHENIUM COMPLEX CATALYST, AND USE THEREOF
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Paragraph 0124-0130, (2021/05/14)
Provided are a novel acyclic carbene ligand for ruthenium complex formation; a ruthenium complex catalyst using the ligand; a method of using the complex as a catalyst in an ethylene-metathesis ethenolysis reaction; a method of preparing the ruthenium complex catalyst; and a method of preparing a linear alpha-olefin, the method including the step of reacting a linear or cyclic alkene compound in the presence of the ruthenium complex catalyst. The acyclic carbene ligand of the present invention and the ruthenium complex catalyst using the same have high selectivity and turnover number for terminal olefin formation in an ethylene-metathesis ethenolysis reaction, and thus linear α-olefins may be prepared with a high yield.
A Cp-based Molybdenum Catalyst for the Deoxydehydration of Biomass-derived Diols
Li, Jing,Lutz, Martin,Klein Gebbink, Robertus J. M.
, p. 6356 - 6365 (2020/11/30)
Dioxo-molybdenum complexes have been reported as catalysts for the deoxydehydration (DODH) of diols and polyols. Here, we report on the DODH of diols using [Cp*MoO2]2O as catalyst (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl). The DODH reaction was optimized using 2 mol % of [Cp*MoO2]2O, 1.1 equiv. of PPh3 as reductant, and anisole as solvent. Aliphatic vicinal diols are converted to the corresponding olefins by [Cp*MoO2]2O in up to 65 % yield (representing over 30 turnovers per catalyst) and 91 % olefin selectivity, which rivals the performance of other Mo-based DODH catalysts. Remarkably, cis-1,2-cyclohexanediol, which is known as quite a challenging substrate for DODH catalysis, is converted to 30 % of 1-cyclohexene under optimized reaction conditions. Overall, the mass balances (up to 79 %) and TONs per Mo achievable with [Cp*MoO2]2O are amongst the highest reported for molecular Mo-based DODH catalysts. A number of experiments aimed at providing insight in the reaction mechanism of [Cp*MoO2]2O have led to the proposal of a catalytic pathway in which the [Cp*MoO2]2O catalyst reacts with the diol substrate to form a putative nonsymmetric dimeric diolate species, which is reduced in the next step at only one of its Mo-centers before extrusion of the olefin product.
