10345-87-6Relevant articles and documents
2-Quinoxalinol diamine Cu(II) complex: Facilitating catalytic oxidation through dual mechanisms
Li, Yuancheng,Lee, Taebum,Weerasiri, Kushan,Wang, Tanyu,Buss, Emily E.,McKee, Michael L.,Gorden, Anne E. V.
, p. 13578 - 13583 (2014)
The Cu(II) complex 1, Cu(II)-6-N-3,5-di-tert-butylsalicylidene-6,7- quinoxalinol-diamine, has been developed to address problems with current methods of catalytic oxidation using tert-butyl hydroperoxide (TBHP). Complex 1 demonstrated an increased capability to utilize TBHP while limiting interference from free radical reactions and was demonstrated to be highly effective in the oxidations of a variety of olefins. the Partner Organisations 2014.
Copper-catalyzed aerobic oxidative rearrangement of tertiary allylic alcohols mediated by TEMPO
Vatèle, Jean-Michel
, p. 2143 - 2145 (2009)
A mild method for the oxidative rearrangement of tertiary allylic alcohols to β-substituted enones using a TEMPO/CuCl2 system, in the presence of molecular sieves, is described. Depending on the substrate, CuCl2 was used in either a catalytic amount under an oxygen atmosphere or stoichiometrically. Georg Thieme Verlag Stuttgart.
Mild manganese(III) acetate catalyzed allylic oxidation: Application to simple and complex alkenes
Shing, Tony K. M.,Yeung, Ying-Yeung,Su, Pak L.
, p. 3149 - 3151 (2006)
Manganese(III) acetate catalyzed allylic oxidation of alkenes to the corresponding enones was investigated, showing excellent regioselectivity and chemoselectivity (functional group compatibility). Δ5-Steroids were transformed into bioactive Δ5-en-7-ones under a nitrogen atmosphere, whereas simple alkenes were converted into the corresponding enones under an oxygen atmosphere in good yields.
Palladium-catalyzed conjugate addition of organosiloxanes to α,β-unsaturated carbonyl compounds and nitroalkenes
Denmark, Scott E.,Amishiro, Nobuyoshi
, p. 6997 - 7003 (2003)
The addition of aryltrialkoxysilanes to α,β-unsaturated carbonyl compounds (ketones, aldehydes) and nitroalkenes in the presence of SbCl3, TBAF, AcOH, and a catalytic amount of Pd(OAc)2, in CH3CN at 60 °C, provides the corresponding conjugate addition products in moderate to good yields. The addition of equimolar amounts of SbCl3 and TBAF is necessary for this reaction to proceed smoothly. The arylpalladium complex, which is generated by the transmetalation from a putative hypercoordinate silicon compound, is considered to be the catalytically active species.
Oxygen as single oxidant for two steps: Base-free one-pot Pd(ii)-catalyzed alcohol oxidation & arylation to halogen-intact β-aryl α,β-enones
Vellakkaran, Mari,Andappan, Murugaiah M. S.,Nagaiah, Kommu
, p. 45490 - 45494 (2014)
Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt. This one-pot green method does not require copper salt, base, and intermediate isolation. Halogen-bearing chalcones, dibenzylideneacetones and arylalkyl enones were synthesized in good yields. This journal is
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Dauben,W.G.,Michno,D.M.
, p. 682 - 685 (1977)
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A MIMIC STUDY ON COENZYME-B12 USING ORGANOCOBALOXIMES. THE REARRANGEMENT OF 1-SUBSTITUTED-2-OXOCYCLOPENTYLMETHYL RADICAL
Tada, Masaru,Miura, Kyo,Okabe, Masami,Seki, Shigetaka,Mizukami, Hideyuki
, p. 33 - 36 (1981)
The radical cleavage of the carbon-cobalt bond of 1-phenyl-2-oxocyclopentylmethyl cobaloxime (1) and 1-ethoxycarbonyl-2-oxocyclopentylmethyl cobaloxime (2) gave only 3-phenylcyclohex-2-enone (7) and 3-ethoxycarbonylcyclohex-2-enone (8), respectively, by acyl migration.This rearrangement may be a reasonable mimicry of the ester migration mediated by coenzyme-B12.
Synthesis and catalytic activities of PdII-phosphine complexes modified poly(ether imine) dendrimers
Krishna, Thatavarathy Rama,Jayaraman, Narayanaswamy
, p. 10325 - 10334 (2004)
In this paper, we report synthesis of new alkyldiphenyl phosphine ligand modified poly(ether imine) dendrimers up to the third generation. The phosphinated dendrimers were obtained by functional group transformations of the alcohols present at the periphery of the dendrimers to chloride, followed by phosphination using LiPPh2. The modification at the peripheries of the dendrimers was performed successfully to obtain up to 16 alkyl diphenylphosphines in the case of a third generation dendrimer, in good yields for each individual step. After phosphination, dendritic ligands were complexed with Pd(COD)Cl2 to give dendritic phosphine-PdII complexes. Both the ligands and the metal complexes were characterized by spectroscopic and spectrometric techniques including high-resolution mass spectral analysis for the lower generations. Evaluation of the catalytic efficacies of the dendrimer-PdII metal complexes in mediating a prototypical C-C bond forming reaction, namely the Heck reaction, was performed using various olefin substrates. While the substrate conversion lowered with catalyst in the order from monomer to third generation dendrimer, the second and third generation dendrimers themselves were found to exhibit significantly better catalytic activities than the monomer and the first generation dendrimer. Graphical abstract
Scalable and sustainable electrochemical allylic C-H oxidation
Horn, Evan J.,Rosen, Brandon R.,Chen, Yong,Tang, Jiaze,Chen, Ke,Eastgate, Martin D.,Baran, Phil S.
, p. 77 - 81 (2016)
New methods and strategies for the direct functionalization of C-H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as € classics €. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C-H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C-H oxidation (demonstrated on 100 grams), enabling the adoption of this C-H oxidation strategy in large-scale industrial settings without substantial environmental impact.
Reaction of organolithium reagents with η5-pentadienyl iron complexes: Formation of σ,η3-iron complexes
McDaniel, Keith F.,Kracker II, Larry R.,Thamburaj, Parinbam K.
, p. 2373 - 2376 (1990)
Reaction of organolithium reagents with η5-pentadienyl iron complex 4 occurs at the C2/C4 position of the π-system, generating σ,η3-iron complexes 5. Air oxidation of these σ,η3-iron complexes generates cyclohexenones. Rea
1,4-Addition of Arylsiloxanes to Enones Catalyzed by Dicationic Palladium(II) Complexes in Aqueous Media
Nishikata, Takashi,Yamamoto, Yasunori,Miyaura, Norio
, p. 752 - 753 (2003)
Catalytic 1,4-addition of arylsiloxanes to enones was carried out at 75°C in the presence of a dicationic palladium(II) catalyst in aqueous 1,4-dioxane. A nitrile-free complex generated in situ from Pd(dba)2 and Cu(BF4)2 in the presence of dppe or dppben was recognized to be the best catalyst to achieve high yields for the representative enones and enals.
Cyclopropyl conjugation and ketyl anions: When do things begin to fall apart?
Tanko,Li, Xiangzhong,Chahma, M'Hamed,Jackson, Woodward F.,Spencer, Jared N.
, p. 4181 - 4192 (2007)
Results pertaining to the electrochemical reduction of 1,2- diacetylcyclopropane (5), 1-acetyl-2-phenylcyclopropane (6), 1-acetyl-2-benzoylcyclopropane (7), and 1,2-dibenzoylcyclopropane (8) are reported. While 6?- exists as a discrete species, the barrier to ring opening is very small (107 s-1. For 7 and 8, the additional resonance stabilization afforded by the benzoyl moieties results in significantly lower rate constants for ring opening, on the order of 10 5-106 s-1. Electron transfer to 8 serves to initiate an unexpected vinylcyclopropane → cyclopentene type rearrangement, which occurs via a radical ion chain mechanism. The results for reduction of 5 are less clear-cut: The experimental results suggest that the reduction is unexceptional, with a symmetry coefficient α ≤ 0.5, and reorganization energy consistent with a simple electron-transfer process (one electron reduction, followed by ring opening). In contrast, molecular orbital calculations suggest that 5?- has no apparent lifetime and that reduction of 5 may occur by a concerted dissociative electron transfer (DET) mechanism (i.e., electron transfer and ring opening occur simultaneously). These seemingly contradictory results can be reconciled if the increase in the internal reorganization energy associated with the onset of concerted DET is offset by a lowering of the solvent reorganization energy associated with electron transfer to a more highly delocalized LUMO.
Corey,Boger
, p. 2461 (1978)
Manganese/Bicarbonate-Catalyzed Epoxidation of Lipophilic Alkenes with Hydrogen Peroxide in Ionic Liquids
Tong, Kit-Ho,Wong, Kwok-Yin,Chan, Tak Hang
, p. 3423 - 3425 (2003)
(Equation presented) Effective epoxidation of lipophilic alkenes using hydrogen peroxide was accomplished with the manganese sulfate/bicarbonate catalytic system in an ionic liquid at room temperature.
Allylic oxidation: Easy synthesis of alkenones from activated alkenes with TEMPO
Breton, Tony,Liaigre, Denis,Belgsir, El Mustapha
, p. 2487 - 2490 (2005)
Activated alkenes and dienes are converted into the corresponding alkenone in excellent yields (>90%). In aqueous acetonitrile, the transformations are catalyzed by 2,2,6,6-tetramethyl-1-oxopiperidinium (TEMPO+) in the presence of water and 2,6-lutidine. TEMPO+ cations were regenerated electrochemically from the radical parent (TEMPO.) at a vitreous carbon anode.
Dirhodium(II) caprolactamate: An exceptional catalyst for allylic oxidation
Catino, Arthur J.,Forslund, Raymond E.,Doyle, Michael P.
, p. 13622 - 13623 (2004)
The oxidation of organic molecules represents a fundamentally important chemical process. Particularly important is allylic oxidation, whereby a single methylene unit is converted directly into a carbonyl group. In this communication, we report that dirhodium(II) caprolactamate [Rh2(cap)4] in combination with tert-butyl hydroperoxide (terminal oxidant) effectively catalyzes the allylic oxidation of a variety of olefins and enones. The reaction is completely selective, tolerant of air/moisture, and can be performed with as little as 0.1 mol % catalyst in minutes. A mechanistic proposal involving redox chain catalysis has been put forth, as well as evidence for the intermediacy of a higher valent dirhodium tert-butyl peroxy complex. Copyright
De Boer
, p. 2426,2427 (1974)
Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure
Sung, Kihyuk,Lee, Mi-hyun,Cheong, Yeon-Joo,Kim, Yu Kwon,Yu, Sungju,Jang, Hye-Young
, p. 3090 - 3097 (2021/05/10)
Multi N-heterocyclic carbene(NHC)-modified iridium catalysts were employed in the β-alkylation of alcohols; dimerization of primary alcohols (Guerbet reaction), cross-coupling of secondary and primary alcohols, and intramolecular cyclization of alcohols. Mechanistic studies of Guerbet reaction, including kinetic experiments, mass analysis, and density functional theory (DFT) calculation, were employed to explain the fast reaction promoted by bimetallic catalysts, and the dramatic reactivity increase of monometallic catalysts at the late stage of the reaction. (Figure presented.).
Copper-Catalyzed Enantioselective 1,2-Reduction of Cycloalkenones
Shi, Yongjie,Wang, Jingxin,Yin, Qin,Zhang, Xumu,Chiu, Pauline
supporting information, p. 5658 - 5663 (2021/08/01)
We report an asymmetric 1,2-reduction of cyclic α,β-unsaturated ketones to access various enantiomerically enriched cyclic allylic alcohols under mild conditions, catalyzed by in situ generated copper hydride ligated with (R)-DTBM-C3*-TunePhos. α-Brominated cycloalkenones were reduced with excellent enantioselectivities of up to 98% ee, while substrates that were without α-substituents were reduced chemoselectively, with moderate enantioselectivities.
