594-60-5Relevant academic research and scientific papers
Mechanism of Hydration of Simple Olefins in Aqueous Solution. cis- and trans-Cyclooctene
Chiang, Y.,Kresge, A. J.
, p. 6363 - 6367 (1985)
Rates of hydration of cis- and trans-cyclooctene and 2,3-dimethyl-2-butene to the corresponding alcohols have been measured in concentrated and dilute aqueous perchloric acid, and those of the latter two olefins in bisulfate ion and phosphoric acid buffer solutions as well.The systems examined in buffers show general-acid catalysis.The reaction of trans-cyclooctene is not reversible, but those of cis-cyclooctene and 2,3-dimethyl-2-butene are; for cis-cycloctene, K=/=1.8 and for 2,3-dimethyl-2-butene, K ca. 4.For hydration of trans-cyclooctene, ΔH*= 22 kcal mol-1, ΔS*= 1 cal K-1 mol-1, and kH(1+)(25 deg C)= 5.2x10-4 M-1 s-1; for the hydration of cis-cyclooctene, ΔH*= 24 kcal mol-1, ΔS*= -10 cal K-1 mol-1, and kH(1+)( 25 deg C)= 2.1x10-7 M-1 s-1; and for the rate of approach to equilibrium in the 2,3-dimethyl-2-butene system, kH(1+)( 25 deg C)= 2.9x10-4 M-1 s-1.The lifetime of tertiary carbocations such as that formed by protonation of 2,3-dimethyl-2-butene is estimated to be τ ca. 10-10 s in dilute aqueous solution, which allows this ion to be a viable, solvationally equilibrated intermediate in the hydration reaction.The secondary cyclooctyl cation is likewise judged to be a solvationally equilibrated species in concentrated aqueous acids, with τ ca. 5x10-8 to 5x10-9 s in the 45-55 wt percent HClO4 solutions used for the hydration of cis-cyclooctene.In dilute aqueous solution, however, carbocation lifetimes are shorter, and τ ca. 5x10-12 s is estimated for the cyclooctyl cation in dilute acids such as those used for the hydration of trans-cyclooctene.Species as short-lived as this can probably still be reaction intermediates, but they are not solvationally equilibrated and may have to react by preassociation mechanisms; an argument is presented that shows that such a mechanism is likely not to be required in the hydration of trans-cyclooctene.
Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
Lambert, Tristan H.,Steiniger, Keri A.
supporting information, p. 8013 - 8017 (2021/10/25)
The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
Application method of Grignard reaction
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Paragraph 0026-0039, (2021/03/31)
The invention discloses an application method of a Grignard reaction, belonging to the technical field of organic synthesis. According to the invention, a two-way dropwise adding mode is adopted, andpreparation of a Grignard reagent and a Grignard reaction are carried out at the same time; as the Grignard reaction is carried out while the Grignard reagent is prepared, the concentration of the Grignard reagent in a reaction system is reduced, and coupling side reactions are reduced; the use amount of a solvent in the reaction system is reduced, the accumulation rate of raw materials is increased, yield is increased and cost is reduced; and meanwhile, in the reaction system, the activity of the Grignard reagent in the system is reduced due to the reduction of the concentration of the Grignard reagent, so an explosion risk caused by over-high concentration of the Grignard reagent during storage and reaction of the Grignard reagent is avoided.
METHOXYCARBONYLATION WITH FORMIC ACID AS CO SOURCE
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Paragraph 0045-0047, (2019/02/24)
Process for methoxycarbonylation with formic acid as the CO source.
Palladium-catalyzed selective generation of CO from formic acid for carbonylation of alkenes
Sang, Rui,Kucmierczyk, Peter,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
supporting information, p. 5217 - 5223 (2018/04/24)
A general and selective palladium-catalyzed alkoxycarbonylation of all kinds of alkenes with formic acid (HCOOH, FA) is described. Terminal, di-, tri-, and tetra-substituted including functionalized olefins are converted into linear esters with high yields and regioselectivity. Key-to-success is the use of specific palladium catalysts containing ligands with built-in base, e.g., L5. Comparison experiments demonstrate that the active catalyst system not only facilitates isomerization and carbonylation of alkenes but also promotes the selective decomposition of HCOOH to CO under mild conditions.
Oxidation of Alkanes by Periodate Using a MnV Nitrido Complex as Catalyst
Ma, Li,Chen, Lingjing,Lau, Tai-Chu
, p. 2846 - 2848 (2016/10/25)
The design of catalytic systems that can selectively oxidize unactivated C?H bonds under mild conditions is a challenge to chemists. We report here that the manganese(V) nitrido complex [MnV(N)(CN)4]2? is a highly efficient catalyst for the oxidation of alkanes by periodate (IO4 ?) at ambient conditions. Excellent yields of alcohols and ketones (>95 %) are obtained with a maximum turnover number (TON) of 3000.
Iron-catalyzed oxidation of unreactive C-H bonds: Utilizing bio-inspired axial ligand modification to increase catalyst stability
Haslinger, Stefan,Raba, Andreas,Cokoja, Mirza,P?thig, Alexander,Kühn, Fritz E.
, p. 147 - 153 (2015/10/06)
Three different bio-inspired Fe(II) complexes are applied as powerful catalysts for the oxidation of unreactive C-H bonds under ambient conditions. Cyclohexane as the main model substrate is oxidized to cyclohexanol, cyclohexyl hydroperoxide, and cyclohexanone. Alcohol + cyclohexyl hydroperoxide to ketone ratios ((A + H)/K) of up to 26 are obtained with comparatively high turnovers of up to 43. Bio-inspired modification of the Fe(II) complexes in the axial positions is used to increase catalyst stability toward hydrogen peroxide, leading to an increase in turnovers of up to 34%. Several parameters for the catalytic oxidation are investigated, e.g., the amount and type of oxidant, reaction temperature, and the relative catalyst concentration. Among others, 9,10-dihydroantracene and 2,3-dimethylbutane are used as substrates for the catalytic C-H bond oxidation.
Highly efficient alkane oxidation catalyzed by [MnV(N)(CN) 4]2-. Evidence for [MnVII(N)(O)(CN) 4]2- as an active intermediate
Ma, Li,Pan, Yi,Man, Wai-Lun,Kwong, Hoi-Ki,Lam, William W.Y.,Chen, Gui,Lau, Kai-Chung,Lau, Tai-Chu
, p. 7680 - 7687 (2014/06/10)
The oxidation of various alkanes catalyzed by [MnV(N)(CN) 4]2- using various terminal oxidants at room temperature has been investigated. Excellent yields of alcohols and ketones (>95%) are obtained using H2O2 as oxidant and CF3CH 2OH as solvent. Good yields (>80%) are also obtained using (NH4)2[Ce(NO3)6] in CF 3CH2OH/H2O. Kinetic isotope effects (KIEs) are determined by using an equimolar mixture of cyclohexane (c-C6H 12) and cyclohexane-d12 (c-C6D12) as substrate. The KIEs are 3.1 ± 0.3 and 3.6 ± 0.2 for oxidation by H2O2 and Ce(IV), respectively. On the other hand, the rate constants for the formation of products using c-C6H12 or c-C6D12 as single substrate are the same. These results are consistent with initial rate-limiting formation of an active intermediate between [Mn(N)(CN)4]2- and H2O2 or CeIV, followed by H-atom abstraction from cyclohexane by the active intermediate. When PhCH2C(CH3)2OOH (MPPH) is used as oxidant for the oxidation of c-C6H12, the major products are c-C6H11OH, c-C6H10O, and PhCH2C(CH3)2OH (MPPOH), suggesting heterolytic cleavage of MPPH to generate a Mn=O intermediate. In the reaction of H2O2 with [Mn(N)(CN)4]2- in CF 3CH2OH, a peak at m/z 628.1 was observed in the electrospray ionization mass spectrometry, which is assigned to the solvated manganese nitrido oxo species, (PPh4)[Mn(N)(O)(CN)4] -·CF3CH2OH. On the basis of the experimental results the proposed mechanism for catalytic alkane oxidation by [MnV(N)(CN)4]2-/ROOH involves initial rate-limiting O-atom transfer from ROOH to [Mn(N)(CN)4]2- to generate a manganese(VII) nitrido oxo active species, [MnVII(N)(O) (CN)4]2-, which then oxidizes alkanes (R'H) via a H-atom abstraction/O-rebound mechanism. The proposed mechanism is also supported by density functional theory calculations.
Synthesis, stability and reactivity of the first mononuclear nonheme oxoiron(iv) species with monoamido ligation: A putative reactive species generated from iron-bleomycin
Hitomi, Yutaka,Arakawa, Kengo,Kodera, Masahito
supporting information, p. 7485 - 7487 (2014/07/07)
The preparation and characterisation of an oxoiron(iv) species with monoamido ligation are described. Reactivity studies revealed the important role of the amido ligand in enhancing the ability of oxoiron(iv) complexes to promote hydrogen atom transfer from external alkanes. the Partner Organisations 2014.
Formation of a room temperature stable Fev(o) complex: Reactivity toward unactivated c-h bonds
Ghosh, Munmun,Singh, Kundan K.,Panda, Chakadola,Weitz, Andrew,Hendrich, Michael P.,Collins, Terrence J.,Dhar, Basab B.,Sen Gupta, Sayam
supporting information, p. 9524 - 9527 (2014/07/22)
An FeV(O) complex has been synthesized from equimolar solutions of (Et4N)2[FeIII(Cl)(biuret-amide)] and mCPBA in CH3CN at room temperature. The FeV(O) complex has been characterized by UV-vis, EPR, M?ssbauer, and HRMS and shown to be capable of oxidizing a series of alkanes having C-H bond dissociation energies ranging from 99.3 kcal mol-1 (cyclohexane) to 84.5 kcal mol-1 (cumene). Linearity in the Bell-Evans-Polayni graph and the finding of a large kinetic isotope effect suggest that hydrogen abstraction is engaged the rate-determining step.
