17432-38-1Relevant articles and documents
Photocatalytic Oxygenation of Substrates by Dioxygen with Protonated Manganese(III) Corrolazine
Jung, Jieun,Neu, Heather M.,Leeladee, Pannee,Siegler, Maxime A.,Ohkubo, Kei,Goldberg, David P.,Fukuzumi, Shunichi
, p. 3218 - 3228 (2016)
UV-vis spectral titrations of a manganese(III) corrolazine complex [MnIII(TBP8Cz)] with HOTf in benzonitrile (PhCN) indicate mono- and diprotonation of MnIII(TBP8Cz) to give MnIII(OTf)(TBP8Cz(H)) and [MnIII(OTf)(H2O)(TBP8Cz(H)2)][OTf] with protonation constants of 9.0 × 106 and 4.7 × 103 M-1, respectively. The protonated sites of MnIII(OTf)(TBP8Cz(H)) and [MnIII(OTf)(H2O)(TBP8Cz(H)2)][OTf] were identified by X-ray crystal structures of the mono- and diprotonated complexes. In the presence of HOTf, the monoprotonated manganese(III) corrolazine complex [MnIII(OTf)(TBP8Cz(H))] acts as an efficient photocatalytic catalyst for the oxidation of hexamethylbenzene and thioanisole by O2 to the corresponding alcohol and sulfoxide with 563 and 902 TON, respectively. Femtosecond laser flash photolysis measurements of MnIII(OTf)(TBP8Cz(H)) and [MnIII(OTf)(H2O)(TBP8Cz(H)2)][OTf] in the presence of O2 revealed the formation of a tripquintet excited state, which was rapidly converted to a tripseptet excited state. The tripseptet excited state of MnIII(OTf)(TBP8Cz(H)) reacted with O2 with a diffusion-limited rate constant to produce the putative MnIV(O2?-)(OTf)(TBP8Cz(H)), whereas the tripseptet excited state of [MnIII(OTf)(H2O)(TBP8Cz(H)2)][OTf] exhibited no reactivity toward O2. In the presence of HOTf, MnV(O)(TBP8Cz) can oxidize not only HMB but also mesitylene to the corresponding alcohols, accompanied by regeneration of MnIII(OTf)(TBP8Cz(H)). This thermal reaction was examined for a kinetic isotope effect, and essentially no KIE (1.1) was observed for the oxidation of mesitylene-d12, suggesting a proton-coupled electron transfer (PCET) mechanism is operative in this case. Thus, the monoprotonated manganese(III) corrolazine complex, MnIII(OTf)(TBP8Cz(H)), acts as an efficient photocatalyst for the oxidation of HMB by O2 to the alcohol.
Light-Driven, Proton-Controlled, Catalytic Aerobic C-H Oxidation Mediated by a Mn(III) Porphyrinoid Complex
Neu, Heather M.,Jung, Jieun,Baglia, Regina A.,Siegler, Maxime A.,Ohkubo, Kei,Fukuzumi, Shunichi,Goldberg, David P.
, p. 4614 - 4617 (2015)
The visible light-driven, catalytic aerobic oxidation of benzylic C-H bonds was mediated by a MnIII corrolazine complex. To achieve catalytic turnovers, a strict selective requirement for the addition of protons was established. The resting state of the catalyst was unambiguously characterized by X-ray diffraction as [MnIII(H2O)(TBP8Cz(H))]+, in which a single, remote site on the ligand is protonated. If two remote sites are protonated, however, reactivity with O2 is shut down. Spectroscopic methods revealed that the related MnV(O) complex is also protonated at the same remote site at -60 °C, but undergoes valence tautomerization upon warming.
Aerobic oxidation of alcohols by using a completely metal-free catalytic system
Prebil, Rok,Stavber, Gaj,Stavber, Stojan
supporting information, p. 395 - 402 (2014/01/23)
A metal-free reaction system of air, NH4NO3(cat), 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)(cat), and H +(cat) is introduced as a simple, safe, inexpensive, efficient and chemoselective mediator for aerobic oxidation of various primary and secondary benzyl and alkyl alcohols, including those bearing oxidizable heteroatoms (N, S, O) to the corresponding aldehydes or ketones. Air oxygen under slight overpressure plays the role of the terminal oxidant, which is catalytically activated by redox cycles of nitrogen oxides released from a catalytic amount of NH4NO3 and cocatalyzed by TEMPO (nitroxyl radical compound), under acidic conditions, which are essential for an overall activation of the reaction system. The synthetic value of this reaction system and its green chemical profile was illustrated by a 10 g scale-up experiment, performed in an open-air system by using a renewable and reusable polymer-supported form of TEMPO (OXYNITROXS100). The reaction solvent was recovered by distillation under atmospheric pressure, and the pure final product was isolated under reduced pressure; the acid activators (HCl or H 2SO4) were recovered as ammonium salts. A metal-free reaction system of air/NH4NO3(cat)/TEMPO (cat)/H+(cat) is introduced as a simple, safe, inexpensive, efficient and chemoselective mediator for aerobic oxidation of various primary and secondary benzyl, alkyl and allyl alcohols, including those bearing oxidizable heteroatoms (N, S, O) to the corresponding aldehydes or ketones. Copyright
A direct and mild formylation method for substituted benzenes utilizing dichloromethyl methyl ether-silver trifluoromethanesulfonate
Ohsawa, Kosuke,Yoshida, Masahito,Doi, Takayuki
, p. 3438 - 3444 (2013/06/26)
A silver trifluoromethanesulfonate (AgOTf)-promoted direct and mild formylation of benzenes has been developed. The reaction utilizing dichloromethyl methyl ether (Cl2CHOMe) and AgOTf powerfully formylated various substituted benzenes under temperature conditions as low as -78 C without losing the protecting groups on the phenolic hydroxyl group.
Development of new recyclable reagents and catalytic systems based on hypervalent iodine compounds
Yusubov, Mekhman S.,Zhdankin, Viktor V.
experimental part, p. 185 - 191 (2011/03/19)
Recent advances in the development of polymer-supported iodine(V) oxidants, recyclable monomeric hypervalent iodine(III) reagents and catalytic systems based on hypervalent iodine compounds are discussed. These efficient and environmentally friendly reagents and catalysts are particularly useful for oxidative transformations of alcohols to carbonyl compounds and for oxidations at the benzylic position.
Synthesis of aromatic aldehydes by a fast method involving Kornblum's reaction
Bratulescu, George
experimental part, p. 2748 - 2752 (2009/05/07)
Aromatic aldehydes were synthesized by oxidation of corresponding halides with dimethyl sulfoxide on potassium bicarbonate by microwave irradiation. Short reaction time and high yields were obtained. Copyright Taylor & Francis Group, LLC.
Preparation and reactivity of polymer-supported 2-iodylphenol ethers, an efficient recyclable oxidizing system
Karimov, Rashad R.,Kazhkenov, Zeinul-Gabiden M.,Modjewski, Matthew J.,Peterson, Eric M.,Zhdankin, Viktor V.
, p. 8149 - 8151 (2008/02/13)
(Chemical Equation Presented) Preparation of new recyclable polymer-supported oxidizing reagents based on 2-iodylphenol ethers is described. The synthesis employs commercially available aminomethylated polystyrene or Merrifield resin and affords polymer-supported 2-iodylphenol ethers with loading up to 0.86 mmol/g with respect to IO2 groups. The new reagents effect clean and efficient conversion of a wide range of alcohols, including heteroatomic and unsaturated structures, to the corresponding carbonyl compounds. Recycling of the resins is possible with minimal loss of activity after several reoxidations.
Facile preparation and reactivity of polymer-supported N-(2-lodyl-phenyl)- acylamide, an Efficient Oxidizing System
Ladziata, Uladzimir,Willging, Jeff,Zhdankin, Viktor V.
, p. 167 - 170 (2007/10/03)
(Chemical Equation Presented) A simple three-step preparation of polymer-supported N-(2-iodyl-phenyl)-acylamide (NIPA resin) starting from 2-iodoaniline is described. The resin was obtained with good loading levels (0.7-0.8 mmol g-1) and has been successfully used for efficient oxidation of a diverse collection of alcohols. Thus, treating alcohols with 1.0 equiv of the resin in 1,2-dichloroethane under reflux for 30-60 min allowed rapid and in most cases complete conversion to the corresponding carbonyl compound.
Highly efficient RuCl3-catalyzed disproportionation of (diacetoxyiodo)benzene to iodylbenzene and iodobenzene; leading to the efficient oxidation of alcohols to carbonyl compounds
Yusubov, Mekhman S.,Chi, Ki-Whan,Park, Joo Yeon,Karimov, Rashad,Zhdankin, Viktor V.
, p. 6305 - 6308 (2007/10/03)
(Diacetoxyiodo)benzene (DIB) selectively oxidizes primary and secondary alcohols to the respective carbonyl compounds in the presence of RuCl3 (0.8-1.0 mol %) at room temperature in aqueous acetonitrile. This reaction proceeds via an initial instantaneous Ru-catalyzed disproportionation of DIB to iodobenzene and iodylbenzene with the latter acting as the actual stoichiometric oxidant toward alcohols.
Photochemical nitration by tetranitromethane. Part XXXIV. The photochemical reactions of pentamethylbenzene and hexamethylbenzene with tetranitromethane. The formation and rearrangement of labile adducts from pentamethylbenzene
Eberson, Lennart,Hartshorn, Michael P.,Timmerman-Vaughan, David J.
, p. 1121 - 1136 (2007/10/03)
The photolysis of the charge transfer (CT) complex of tetranitromethane and Pentamethylbenzene (13) in dichloromethane at - 50 or - 78°C gives the labile epimeric 1,2,3,4,6-pentamethyl-3-nitro-6-trinitromethylcyclohexa-1,4-dienes 18 and 19. Adduct 18 rearranges rapidly in [2H2]dichloromethane at 22°C (half-life 9 min) to give 2,3,4,5-tetrarnethyl-1-(2′,2′,2′-trinitroethyl)benzene (21), 2,3,4,5-tetramethylphenylnitromethane (26), 2,3,4,5-tetramethylbenzyl nitrate (32) and 2,3,4,5-tetramethylbenzyl nitrite (36). The photolysis of the tetranitromethane-13 CT complex in dichloromethane at 20°C gives compounds 21, 26, 32 and 36, in addition to their 2,3,4,6-tetramethyl analogues 20, 25, 31 and 35, the latter set of products probably arising from the rearrangement of the highly labile epimeric 1,2,3,5,6-pentamethyl-3-nitro-6-trinitromethylcyclohexa-1,4-dienes 54. The photolysis of the tetranitromethane-13 CT complex in acetonitrile gives mainly the phenylnitromethane 26, while similar reaction in 1,1,1,3,3,3-hexafluoropropan-2-ol yields pentamethylnitrobenzene 24, the latter by a nitrosation/oxidation sequence. Reaction of 13 with nitrogen dioxide in dichloromethane gives mainly compounds 26 and 30. No adducts were detected in the photolysis of the CT complex of hexamethylbenzene 14 in dichloromethane at accessible reaction temperatures (≥ -20°C), but products of side-chain modification 37-46 were formed. In acetonitrile similar reaction gave in addition to the above products 37-46 the N-nitrosoacetamide 47 and its precursor 49. Compounds 47 and 49 are also formed, along with the major products pentamethylbenzyl nitrate 39 and the mono- and di-nitromethyl compounds 40 and 43, on reaction of 14 with nitrogen dioxide in acetonitrile. EPR spectroscopic examination of the photolysis of acidic (trifluoroacetic acid, 0.4 mol dm-3) solutions of tetranitromethane and 13 or 14 demonstrated the formation of the corresponding radical cation or a transformation product thereof, i.e. the 1,2,3,4,5,6,7,8-octamethylanthracene radical cation from 13 or 14·+ from 14. Acta Chemica Scandinavica 1996.
