101-81-5Relevant articles and documents
Serres,Fields
, p. 4685,4686 (1960)
Hypovalent Radicals. 6. Electroreduction of Diazodiphenylmethane-Intermediacy of Ph2CN-. and PhC-.
McDonald, Richard N.,Triebe, F. M.,January, J. R.,Borhani, K. J.,Hawley, M. D.
, p. 7867 - 7872 (1980)
The electrochemical reduction of diazodiphenylmethane (Ph2CN2) at a platinum cathode in DMF-0.1 F (n-Bu)4ClO4 has been shown to afford benzophenone azine ((Ph2C=N-)2) as the principal product, along with lesser amounts of Ph2CH2 and several other compounds.Product formation occurs by a chain process in which the carbene anion radical, Ph2C-., is produced from electrogenerated Ph2CN2-. by rapid loss of nitrogen.Ph2CH-, the first-observed intermediate in Ph2CN2 electroreduction, is obtained from Ph2C-. either by protonation followed by reduction or by hydrogen atom abstraction from a component of the solvent-electrolyte system.Propagation of the chain involves coupling of Ph2CH- with Ph2CN2 to produce Ph2CHN=CPh2 followed by proton transfer from this anion to Ph2C-. to give (Ph2C=N-)22- and Ph2CH., respectively.Regeneration of Ph2CN2-. occurs by electron transfer from either (Ph2C=N-)22- or (Ph2C=N-)2-. to Ph2CN2.Termination of the chain occurs upon protonation of Ph2CH-.In the presence of the electroinactive proton donors, diethyl malonate and 2,2,2-trifluoroethanol, azine formation is interdicted and Ph2C=NNH2 and Ph2CH2 are the two major products.Studies of the Ph2CH2/Ph2C=NNH2 product ratio as a function of proton donor concentration and temperature have established that protonation (and other reactions) of Ph2CN2-. occurs exclusively on terminal nitrogen while Ph2CH2 arises via Ph2C-..No evidence was obtained for either hydrogen atom abstraction by or protonation of Cα of Ph2CN2-..
Benzylation of benzene by benzyl chloride over silica-supported iron sulfate catalysts
Shuvaeva, Maria A.,Nuzhdin, Alexey L.,Martyanov, Oleg N.,Bukhtiyarova, Galina A.
, p. 231 - 232 (2014)
The silica-supported Fe-containing catalysts prepared using FeSO 4 as a precursor exhibit high activity toward the reaction of benzene with benzyl chloride.
Towards iron-catalysed suzuki biaryl cross-coupling: Unusual reactivity of 2-halobenzyl halides
Bedford, Robin B.,Gallagher, Timothy,Pye, Dominic R.,Savage, William
, p. 1761 - 1765 (2015)
The reaction of 2-halobenzyl halides with the borate anion Li[(Ph)(t-Bu)Bpin] leads not only to the expected arylation at the benzyl position, but also to some Suzuki biaryl cross-coupling. Preliminary mechanistic investigations hint towards the intermediacy of benzyl iron intermediates that can either: (a) directly cross-couple with the aryl boron reagent to give observed monoarylated species, or (b) undergo oxidative addition of the aryl halide to generate the diarylated species on reaction with the boron-based nucleophile.
CONTRASTING CHEMISTRY OF DIPHENYLCARBENE AND FLUORENYLIDENE IN CYCLOHEXANE
Savino, T. G.,Senthilnathan, V. P.,Platz, M. S.
, p. 2167 - 2180 (1986)
The chemistry of diphenylcarbene and fluorenylidene in cyclohexane was investigated.An examination of the product distributions, radical scavening experiments and isotopic fractionation established that diphenylcarbene reacts with cyclohexane predominantly, if not exclusively, through its triplet state whereas fluorenylidene exhibits substantial chemistry from its low lying singlet state in addition to some triplet chemistry.The results indicate that the singlet-triplet splitting of fluorenylidene is smaller than in diphenylcarbene.The chemical studies are in accord with previous laser flash photolysis experiments.
Novel coupling reaction of pentaarylantimony with carbon electrophiles
Fujiwara, Masahiro,Tanaka, Mutsuo,Baba, Akio,Ando, Hisanori,Souma, Yoshie
, p. 39 - 42 (1996)
The cross-coupling reactions of pentaarylantimony with organic halides and allyl acetate were studied under various conditions of acetonitrile solvent, palladium catalysts and copper iodide. Acetonitrile solvent enabled a nucleophilic coupling reaction with allylic halides, although a radical reaction and an intramolecular ligand coupling have been regarded as general under other conditions. Palladium catalysts were effective for the coupling reaction with allyl acetate. Copper iodide promoted the reaction of organic halides, such as methyl iodide and ethyl bromoacetate. In the latter two cases, the formation of diaryls is a significant side reaction.
Photoinduced Cleavage of the C-C Bonds of 9-Alkyl-10-methyl-9,10-dihydroacridines by Perchloric Acid
Fukuzumi, Shunichi,Tokuda, Yoshihiro,Fujita, Morifumi
, p. 1905 - 1908 (1991)
The C-C single bonds of 9-alkyl-10-methyl-9,10-dihydroacridines are readily cleaved by perchloric acid in acetonitrile under irradiation of the absorption band of AcrHR to yield the corresponding alkane (RH) and 10-methylacridinium ion (AcrH+).
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Bachmann
, p. 3005,3007 (1933)
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Oxime Carbapalladacycle Covalently Anchored to High Surface Area Inorganic Supports or Polymers as Heterogeneous Green Catalysts for the Suzuki Reaction in Water
Baleizao, Carlos,Corma, Avelino,Garcia, Hermenegildo,Leyva, Antonio
, p. 439 - 446 (2004)
An oxime carbapalladacycle known as an extremely active homogeneous catalyst for the Suzuki coupling in water has been conveniently modified and anchored on high surface area SiO2, MCM-41, and polystyrene-divinylbenzene and ethylenglycol dimethylacrylate polymers. The resulting solids were characterized by analytical and spectroscopic (UV-vis and IR) techniques and tested as catalysts for the reaction of 4-chloroacetophenone with phenylboronic acid in water, dioxane, and a mixture of both. Differences in activity depending on the support were remarkable, the palladium complex being more active for the reactions in water when supported on SiO2 or MCM-41. The catalysts were truly heterogeneous (no leached palladium) and when anchored on SiO2 were reused seven times without loosing activity. Palladium complex anchored in SiO2 was also tested as Suzuki catalyst for a wide range of bromo-, chloro-, and even fluoroaromatics.
Nanoporous hematite nanoparticles: Synthesis and applications for benzylation of benzene and aromatic compounds
Cuong, Nguyen Duc,Hoa, Nguyen Duc,Hoa, Tran Thai,Khieu, Dinh Quang,Quang, Duong Tuan,Quang, Vu Van,Hieu, Nguyen Van
, p. 83 - 87 (2014)
The catalytic benzylation of benzene and other aromatic compounds is one of the most important reactions in the synthesis of pharmaceutical compounds. In this study, we report the synthesis of nanoporous α-Fe2O 3 nanoparticles via a hydrothermal method and their application in the catalytic benzylation of benzene and benzyl chloride in the fabrication of diphenylmethane. Crystal structure and morphology characterization results demonstrated that the hydrothermal method enabled the fabrication of highly dispersed α-Fe2O3 nanoparticles with spherical shape and an average size of 100 nm. The α-Fe2O3 nanoparticles have nanopores of less than 10 nm that are randomly distributed inside the nanoparticles. The catalytic benzylation of benzene and benzyl chloride was conducted over the synthesized a-Fe2O3 nanoparticles. The results demonstrated that the synthesized a-Fe 2O3 nanoparticles are effective catalysts for the benzylation of benzene and benzyl chloride with high activity and selectivity.
Directing zeolite structures into hierarchically nanoporous architectures
Na, Kyungsu,Jo, Changbum,Kim, Jeongnam,Cho, Kanghee,Jung, Jinhwan,Seo, Yongbeom,Messinger, Robert J.,Chmelka, Bradley F.,Ryoo, Ryong
, p. 328 - 332 (2011)
Crystalline mesoporous molecular sieves have long been sought as solid acid catalysts for organic reactions involving large molecules. We synthesized a series of mesoporous molecular sieves that possess crystalline microporous walls with zeolitelike frameworks, extending the application of zeolites to the mesoporous range of 2 to 50 nanometers. Hexagonally ordered or disordered mesopores are generated by surfactant aggregates, whereas multiple cationic moieties in the surfactant head groups direct the crystallization of microporous aluminosilicate frameworks. The wall thicknesses, framework topologies, and mesopore sizes can be controlled with different surfactants. The molecular sieves are highly active as catalysts for various acid-catalyzed reactions of bulky molecular substrates, compared with conventional zeolites and ordered mesoporous amorphous materials.
Jones et al.
, p. 175 (1978)
Reactions of diazirines with aluminum chloride: Lewis acid-mediated carbene generation and friedel-crafts reactions [22]
Moss,Fede,Yan
, p. 9878 - 9879 (2000)
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Synthesis of diarylmethane derivatives from Stille cross-coupling reactions of benzylic halides
Nichele, Tatiana Z.,Monteiro, Adriano L.
, p. 7472 - 7475 (2007)
A catalyst precursor prepared in situ from palladium acetate and a phosphine ligand was used for the Stille cross-coupling reaction of benzylic bromides and chlorides with aryltributyltin analogues. The reactions were performed at 80 °C using dppf as ligand in the presence of KF, or more conveniently using PPh3 in the absence of base, furnishing diarylmethane derivatives in high yields (86-99%). Using Pd(OAc)2/PPh3 as catalyst precursor competitive Stille and Suzuki cross-coupling reactions with benzyl chloride showed that in the absence of base or in the presence of KF the Stille product is the majority product, and only the Suzuki product was obtained in the presence of KOH as base.
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Olah,G.A.,Surya Prakash,G.K.
, p. 397 - 398 (1978)
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EVIDENCE FOR SINGLE ELECTRON TRANSFER IN THE REDUCTION OF ALCOHOLS WITH LITHIUM ALUMINIUM HYDRIDE
Ashby, E. C.,Goel, A. B.
, p. 1879 - 1880 (1981)
EPR evidence supporting a single electron transfer mechanism in the reduction of secondary and tertiary alcohols to hydrocarbons with LiAlH4 is presented.
Evidence for Carbocation Intermediates in the TiO2-Catalyzed Photochemical Fluorination of Carboxylic Acids
Lai, Cuiwei,Kim, Yeong Il,Wang, Chong Mou,Mallouk, Thomas E.
, p. 1393 - 1399 (1993)
Laser flash photolysis/transient absorbance spectroscopy was used to determine the mechanism of photo-Kolbe fluorination of carboxylic acids, RCOOH --> RF, at colloidal TiO2 suspensions in acetonitrile.Transient absorption spectra of Ph3C(+), Ph3C(*), Ph2CH(*) and Ph2CH(+) were observed from the photooxidation of Ph3CCOOH and Ph2CHCOOH at TiO2 using 355-nm excitation.Transient decays, monitored in the presence and absence of fluoride ions, showed that the carbocations reacted rapidly with fluoride, but the neutral radicals did not.By varying the laser intensity, it wa s found that the photooxidation of Ph3CCOOH to Ph3C(*) at TiO2 occured via a single-photon process, while the formation of of Ph3C(+) required two photons.This finding is in agreement with the parabolic light intensity dependence of initial reaction rates in bulk photolysis experiments.Although fluoride is strongly adsorbed on the TiO2 surface in acetonitrile solution, the oxidizing power of photogenerated holes could be increased by coordinating HF to F(-), and therefore the threshold for oxidative photochemical fluorination was extented to more positive potentials.In this way less easily oxidized carboxylic acids RCOOH could be converted to RF.
Synthesis of unsymmetrical diarylmethanes by cross-coupling between aryl triflates and tetrabutylammonium difluorotribenzylstannate
Garcia Martinez, Antonio,Osio Barcina, Jose,Heras, Maria Del Rosario Colorado,De Fresno Cerezo, Alvaro
, p. 1377 - 1378 (2000)
(Matrix Presented) The benzylation of aryl triflates can be achieved by cross-coupling between aryl triflates and the new hypervalent tin reagent (n-Bu4N)+(Bn3-SnF2)-.
Insights into the role of new palladium pincer complexes as robust and recyclable precatalysts for suzuki-miyaura couplings in neat water
Ines, Blanca,Sanmartin, Raul,Moure, Maria Jesus,Dominguez, Esther
, p. 2124 - 2132 (2009)
Suzuki-Miyaura biaryl and diarylmethane syntheses via the coupling of arylboronic acids with aryl and arylmethyl bromides are performed in water by means of two new CNC-type palladium pincer complexes. Good to excellent results (including high TON values and extended recycling procedures) are obtained in most cases for a range of electronically dissimilar halides and boronic acids. On the basis of a series of kinetics studies, transmission electron microscopy (TEM), mercury drop tests, and quantitative poisoning experiments, the real role of the latter palladacycles, closely linked to the formation and active participation of palladium nanoparticles, is discussed.
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Maekawa,K. et al.
, p. 3478 - 3481 (1973)
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KOtBu: A Privileged Reagent for Electron Transfer Reactions?
Barham, Joshua P.,Coulthard, Graeme,Emery, Katie J.,Doni, Eswararao,Cumine, Florimond,Nocera, Giuseppe,John, Matthew P.,Berlouis, Leonard E. A.,McGuire, Thomas,Tuttle, Tell,Murphy, John A.
, p. 7402 - 7410 (2016)
Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes, and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction.
An inexpensive and highly stable ligand 1,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)piperazine for Mizoroki-Heck and room temperature Suzuki-Miyaura cross-coupling reactions
Mohanty, Sasmita,Suresh,Balakrishna, Maravanji S.,Mague, Joel. T.
, p. 240 - 247 (2008)
A bulky, inexpensive and simple bidentate ligand 1,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)piperazine (1) has been synthesized and characterized. The palladium catalyst was formed by combination of 1 with [Cl2Pd(COD)] in a ratio of 1:1, tested in the Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions. Coupling of a variety of aryl bromides with phenylboronic acid using methanol as solvent at room temperature, or at 60 °C, gave generally high yields of coupled products. Coupling of aryl chlorides with organoboron reagent at 110 °C in DMF afforded good yields of biaryls under aerobic conditions. This non-phosphorus, air and moisture stable catalyst also displays good activity for Mizoroki-Heck coupling reaction in methanol at 60 °C with various aryl chlorides and bromides.
Direct Formation of Organocopper Compounds by Oxidative Addition of Zerovalent Copper to Organic Halides
Ebert, Greg W.,Rieke, Reuben D.
, p. 5280 - 5282 (1984)
Mixing a solution of CuI*P(Et)3 with a stoichiometric amount of lithium naphthalide in THF affords a zerovalent copper species that is sufficiently reactive to add to organic halides to give the corresponding organocopper compounds.
Absolute asymmetric photoreactions of acridines with diphenylacetic acid in their cocrystals
Koshima, Hideko
, p. 207 - 214 (2005)
Solid-state photodecarboxylation occurs in a chiral cocrystal of acridine and diphenylacetic acid to afford a chiral condensation product in modest enantiomeric excess. A chiral cocrystal of 9-methylbenz[c]acridine and diphenylacetic acid also undergoes similar photodecarboxylation but gives an almost racemic product. The different enantioselectivities between the two chiral cocrystals can be understood on the basis of the molecular arrangements in the lattice.
Palladium-catalyzed carbonylative suzuki coupling of benzyl halides with potassium aryltrifluoroborates in aqueous media
Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
, p. 788 - 792 (2011)
A general palladium-catalyzed carbonylative cross-coupling reaction of benzyl chlorides with potassium aryltrifluoroborates in water has been developed. Applying this improved methodology 16 different 1,2-diarylethanones have been synthesized in 40-89% yield. Copyright
Nickel-catalyzed reductive deoxygenation of diverse C-O bond-bearing functional groups
Cook, Adam,MacLean, Haydn,St. Onge, Piers,Newman, Stephen G.
, p. 13337 - 13347 (2021/11/20)
We report a catalytic method for the direct deoxygenation of various C-O bond-containing functional groups. Using a Ni(II) pre-catalyst and silane reducing agent, alcohols, epoxides, and ethers are reduced to the corresponding alkane. Unsaturated species including aldehydes and ketones are also deoxygenated via initial formation of an intermediate silylated alcohol. The reaction is chemoselective for C(sp3)-O bonds, leaving amines, anilines, aryl ethers, alkenes, and nitrogen-containing heterocycles untouched. Applications toward catalytic deuteration, benzyl ether deprotection, and the valorization of biomass-derived feedstocks demonstrate some of the practical aspects of this methodology.
Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon
Thorwart, Thadd?us,Roth, Daniel,Greb, Lutz
supporting information, p. 10422 - 10427 (2021/05/27)
Given its earth abundance, silicon is ideal for constructing Lewis acids of use in catalysis or materials science. Neutral silanes were limited to moderate Lewis acidity, until halogenated catecholato ligands provoked a significant boost. However, catalytic applications of bis(perhalocatecholato)silanes were suffering from very poor solubility and unknown deactivation pathways. In this work, the novel per(trifluoromethyl)catechol, H2catCF3, and adducts of its silicon complex Si(catCF3)2 (1) are described. According to the computed fluoride ion affinity, 1 ranks among the strongest neutral Lewis acids currently accessible in the condensed phase. The improved robustness and affinity of 1 enable deoxygenations of aldehydes, ketones, amides, or phosphine oxides, and a carbonyl-olefin metathesis. All those transformations have never been catalyzed by a neutral silane. Attempts to obtain donor-free 1 attest to the extreme Lewis acidity by stabilizing adducts with even the weakest donors, such as benzophenone or hexaethyl disiloxane.
Bis(perfluoropinacolato)silane: A Neutral Silane Lewis Superacid Activates Si?F Bonds
Greb, Lutz,Hanusch, Franziska,Inoue, Shigeyoshi,Thorwart, Thadd?us,Tschernuth, Florian S.
supporting information, p. 25799 - 25803 (2021/11/09)
Despite the earth abundance and easy availability of silicon, only few examples of isolable neutral silicon centered Lewis superacids are precedent in the literature. To approach the general drawbacks of limited solubility and unselective deactivation pathways, we introduce a Lewis superacid, based on perfluorinated pinacol substituents. The compound is easily synthesized on a gram-scale as the corresponding acetonitrile mono-adduct 1?(MeCN) and was fully characterized, including single crystal X-ray diffraction analysis (SC-XRD) and state-of-the-art computations. Lewis acidity investigations by the Gutmann-Beckett method and fluoride abstraction experiments indicate a Lewis superacidic nature. The challenging Si?F bond activation of Et3SiF is realized and promising catalytic properties are demonstrated, consolidating the potential applicability of silicon centered Lewis acids in synthetic catalysis.
