4393-05-9Relevant articles and documents
Gallium-assisted transfer hydrogenation of alkenes
Michelet, Bastien,Bour, Christophe,Gandon, Vincent
supporting information, p. 14488 - 14492 (2015/04/16)
We report a rare case of alkene transfer hydrogenation using a main-group compound instead of a transition-metal complex as catalyst. We disclosed that 1, 4-cyclo-hexadiene can be used as H2 surrogate towards olefin reduction in the presence of [IPrGaCl2][SbF6]. Hydrogenative cycli-zations have also been carried out because this cationic gallium complex is also a potent hydroarylation catalyst.
Unified view of oxidative C-H bond cleavage and sulfoxidation by a nonheme iron(IV)-oxo complex via lewis acid-promoted electron transfer
Park, Jiyun,Morimoto, Yuma,Lee, Yong-Min,Nam, Wonwoo,Fukuzumi, Shunichi
supporting information, p. 3618 - 3628 (2014/05/06)
Oxidative C-H bond cleavage of toluene derivatives and sulfoxidation of thioanisole derivatives by a nonheme iron(IV)-oxo complex, [(N4Py)Fe IV(O)]2+ (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl) methylamine), were remarkably enhanced by the presence of triflic acid (HOTf) and Sc(OTf)3 in acetonitrile at 298 K. All the logarithms of the observed second-order rate constants of both the oxidative C-H bond cleavage and sulfoxidation reactions exhibit remarkably unified correlations with the driving forces of proton-coupled electron transfer (PCET) and metal ion-coupled electron transfer (MCET) in light of the Marcus theory of electron transfer when the differences in the formation constants of precursor complexes between PCET and MCET were taken into account, respectively. Thus, the mechanisms of both the oxidative C-H bond cleavage of toluene derivatives and sulfoxidation of thioanisole derivatives by [(N4Py)FeIV(O)]2+ in the presence of HOTf and Sc(OTf)3 have been unified as the rate-determining electron transfer, which is coupled with binding of [(N4Py)FeIV(O)]2+ by proton (PCET) and Sc(OTf)3 (MCET). There was no deuterium kinetic isotope effect (KIE) on the oxidative C-H bond cleavage of toluene via the PCET pathway, whereas a large KIE value was observed with Sc(OTf)3, which exhibited no acceleration of the oxidative C-H bond cleavage of toluene. When HOTf was replaced by DOTf, an inverse KIE (0.4) was observed for PCET from both toluene and [Ru II(bpy)3]2+ (bpy =2,2′-bipyridine) to [(N4Py)FeIV(O)]2+. The PCET and MCET reactivities of [(N4Py)FeIV(O)]2+ with Bronsted acids and various metal triflates have also been unified as a single correlation with a quantitative measure of the Lewis acidity.
Simultaneous production of p-tolualdehyde and hydrogen peroxide in photocatalytic oxygenation of p-xylene and reduction of oxygen with 9-mesityl-10-methylacridinium ion derivatives
Ohkubo, Kei,Mizushima, Kentaro,Iwata, Ryosuke,Souma, Kazunori,Suzuki, Nobuo,Fukuzumi, Shunichi
supporting information; experimental part, p. 601 - 603 (2010/05/01)
Photooxygenation of p-xylene by oxygen occurs efficiently under photoirradiation of 9-mesityl-2,7,10-trimethylacridinium ion (Me 2Acr+-Mes) to yield p-tolualdehyde and hydrogen peroxide, which is initiated via photoinduced electron transfer of Me2Acr +-Mes to produce the electron-transfer state.
Catalytic Oxidation of Alkylbenzenes with Molecular Oxygen under Normal Pressure and Temperature by N-Hydroxyphthalimide Combined with Co(OAc)2
Yoshino, Yasushi,Hayashi, Yoshiaki,Iwahama, Takahiro,Sakaguchi, Satoshi,Ishii, Yasutaka
, p. 6810 - 6813 (2007/10/03)
A practical catalytic method to convert alkylbenzenes into the corresponding carboxylic acids under atmospheric dioxygen at ambient temperature using a combined catalytic system consisting of N-hydroxyphthalimide (NHPI) and Co(OAc)2 was developed. For instance, the oxidation of toluene was completed by NHPI combined with Co(OAc)2 under an oxygen atmosphere at room temperature to give benzoic acid in 81% yield. Under these conditions, o- and p-xylenes were selectively converted into the corresponding monocarboxylic acids without the formation of the dicarboxylic acids. ESR measurements showed that Co(II) species assists in the formation of phthalimide-N-oxyl (PINO), which is a key species in this oxidation, from NHPI.
Photochemical nitration by tetranitromethane. Part XXXIII. Adduct formation in the photochemical reactions of 1,2,4,5- and 1,2,3,5-tetramethylbenzene
Butts, Craig P.,Eberson, Lennart,Fulton, Karen L.,Hartshorn, Michael P.,Robinson, Ward T.,Timmerman-Vaughan, David J.
, p. 991 - 1008 (2007/10/03)
The photolysis of the charge-transfer complex of tetranitromethane and 1,2,4,5-tetramethylbenzene in dichloromethane or acetonitrile gives the epimeric 1,3,4,6-tetramethyl-3-nitro-6-trinitromethylcyclohexa-1,4-dienes 8 and 9, in addition to products of nuclear nitration 12 and side-chain modification 10, 11, and 13-18. Similar reactions of 1,2,3,5-tetramethylbenzene gave trans-1,3,5,6-tetramethyl-6-nitro-3-trinitromethylcyclohexa-1,4-diene 30 and two isomeric 'double' adducts 31 and 32, in addition to products of nuclear nitration 27 and side-chain modification 26, 28 and 29. The eliminative rearrangements of adducts 8 and 30 to give re-aromatized products in acetonitrile or [2H3] acetonitrile and in [2H] chloroform are reported. The photolysis of the charge-transfer complexes of tetranitromethane with either 1,2,4,5-tetramethylbenzene or 1,2,3,5-tetramethylbenzene in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) gives a marked increase in the yields of ring-nitration products 12 or 27, respectively, reactions presumed to proceed via a nitrosation-oxidation sequence. Reaction of 1,2,4,5-tetramethylbenzene with excess nitrogen dioxide in HFP also results in extensive ring nitration to give 12 and 2,3,5,6-tetramethyl-1,4-dinitrobenzene (25); the latter compound is seen as arising via the 2,3,5,6-tetramethyl-1,4-dinitrosobenzene (34). Similar reaction of 1,2,3,5-tetramethylbenzene gives ring-nitration product 27 as the major product. X-Ray crystal structures are reported for 2,4,6-trimethyl-1-(2′,2′,2′-trinitroethyl)benzene (26) and trans-1,3,5,6-tetramethyl-6-nitro-3-trinitromethyl-cyclohexa-1,4-diene (30). Acta Chemica Scandinavica 1996.
SELECTIVE ONE-POT OXIDATION OF METHYLARENES TO BENZYL ALCOHOLS WITH THE COPPER(II)-PEROXYDISULFATE SYSTEM
Cort, Antonella Dalla,Mandolini, Luigi,Panaioli, Sandro
, p. 613 - 616 (2007/10/02)
Methylarenes with low oxidation potential are selectively nitrooxylated by Cu(NO3)2/Na2S2O8/NaNO3 in Me2SO.Subsequent hydrolysis of the benzyl nitrates affords benzyl alcohols in fairly good yields.
Photochemically Induced Oxygenation of Methylbenzenes, Bibenzyls, and Pinacols in the Presence of Naphtalene-1,4-dicarbonitrile
Albini, Angelo,Spreti, Silvia
, p. 1175 - 1180 (2007/10/02)
The photochemical reaction of aromatic donors in oxygen-saturated solution in the presence of naphtalene-1,4-dicarbonitrile (NDN) has been investigated.Methylbenzenes (1a,b) are found to give benzaldehydes, bibenzyls (4a-d) are cleaved to benzaldehydes (or phenyl ketones) and benzylalcohols, pinacols (7a-c) and pinacol ethers (9b,c) are likewise cleaved to carbonyl derivates (in the latter case also to esthers).The mechanism of this reaction is discussed on the basis of product distribution and quantum yield both in the absence and inj the presence of oxygen, and involves electron-transfer from the donors to the NDN singlet excited state and deprotonation or carbon-carbon bond cleavage of the radical cation, followed by reaction of the benzyl radicals with oxygen.
Photooxidation of Methylbenzenes and Methylnaphthalenes Sensitized by Cyanoanthracenes
Albini, Angelo,Spreti, Silvia
, p. 1286 - 1292 (2007/10/02)
9-Cyanoanthracene, 9,10-dicyanoanthracene and 3,7,9,10-tetracyanoanthracene photosensitize the oxidation in acetonitrile of toluene, durene, hexamethylbenzene, 1-methyl- and 2-methylnaphthalene to the corresponding aldehydes, with low yield of the alcohols and, in the case of hexamethylbenzene, of tetramethylphthalide.In benzene, only hexamethylbenzene reacts through a different pathway involving singlet oxygen.Comparison with fluorescence quenching data and experiments in the presence of good donors, halides or radical traps, as well as the effect of solvents and of oxy gen concentration show that the reaction involves electron transfer from the methylaromatic to the singlet excited state of the sensitizer, followed by proton transfer to CA or O2 yielding benzyl radicals, which react with oxygen or can be trapped. - Keywords: Photooxidation, Methylbenzenes, Methylnaphthalenes, Cyanoanthracenes
