1003-66-3Relevant articles and documents
Mechanistic Insight into Weak Base-Catalyzed Generation of Carbon Monoxide from Phenyl Formate and Its Application to Catalytic Carbonylation at Room Temperature without Use of External Carbon Monoxide Gas
Konishi, Hideyuki,Matsubara, Mika,Mori, Keisuke,Tokiwa, Takaki,Arulmozhiraja, Sundaram,Yamamoto, Yuta,Ishikawa, Yoshinobu,Hashimoto, Hiroshi,Shigeta, Yasuteru,Tokiwa, Hiroaki,Manabe, Kei
, p. 3592 - 3601 (2017)
The mechanisms of the weak base-catalyzed generation of carbon monoxide (CO) and phenol from phenyl formate were investigated by experimental and theoretical methods. Kinetic studies revealed a first-order reaction in both phenyl formate and the base. The reaction was found to proceed by an E2 α-elimination pathway, which involves the abstraction of the formyl proton of phenyl formate, simultaneously generating CO and phenoxide. The reaction rate was affected by the substituents on phenyl formate, the polarity of solvents, and the basicity of bases. The mechanistic insight obtained from these studies permitted the chemical control of the rate of CO generation, which was the key to the development of the external CO-free Pd-catalyzed phenoxycarbonylation of haloarenes at room temperature. Because of the mild reaction conditions and wide substrate scope, this phenoxycarbonylation constitutes a general, safe, and practical method to synthesize arenecarboxylic acid esters. (Figure presented.).
Ion-Molecule Complexes in Unimolecular Fragmentations of Gaseous Cations. Cyclization of Unsaturated Carbocations in the Gas Phase
Hall, David G.,Morton, Thomas Hellman
, p. 5686 - 5688 (1980)
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Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation
Zheng, Yi-Wen,Chen, Bin,Ye, Pan,Feng, Ke,Wang, Wenguang,Meng, Qing-Yuan,Wu, Li-Zhu,Tung, Chen-Ho
, p. 10080 - 10083 (2016)
We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.
A New Method for Obtaining Isotopic Fractionation Data at Multiple Sites in Rapidly Exchanging Systems
Jarret, Ronald M.,Saunders, Martin
, p. 2648 - 2654 (1985)
A new method for rapidly and conveniently obtaining isotopic fractionation factors in dilute aqueous solutions of compounds containing rapidly exchanging OH, NH, and SH groups is described.Shifts in the positions of NMR peaks for spectroscopically observable nuclei induced by isotopic substitution are the basis of this procedure which has the unique capability of separately measuring the isotopic exchange constants simultaneously for several different groups in the same molecule.The results for a series of alcohols, amines, thiols, phenols, acids, and amides with use of 13C NMR spectroscopy are reported.Atypically low values of Kfrac are observed in several cases, indicating that there are strong internal hydrogen bonds in competition with those to water, yielding conformational information.
Negligible Isotopic Effect on Dissociation of Hydrogen Bonds
Ge, Chuanqi,Shen, Yuneng,Deng, Gang-Hua,Tian, Yuhuan,Yu, Dongqi,Yang, Xueming,Yuan, Kaijun,Zheng, Junrong
, p. 3187 - 3195 (2016)
Isotopic effects on the formation and dissociation kinetics of hydrogen bonds are studied in real time with ultrafast chemical exchange spectroscopy. The dissociation time of hydrogen bond between phenol-OH and p-xylene (or mesitylene) is found to be iden
Synthesis and Properties of 1-Acyl Triazenes
Landman, Iris R.,Acu?a-Bolomey, Emilio,Scopelliti, Rosario,Fadaei-Tirani, Farzaneh,Severin, Kay
supporting information, p. 6408 - 6412 (2019/09/06)
1-Acyl triazenes can be prepared by acid-catalyzed hydration, gold/iodine-catalyzed oxidation, or oxyhalogenation of 1-alkynyl triazenes. Crystallographic analyses reveal a pronounced effect of the acyl group on the electronic structure of the triazene fu
Electrocatalytic Reduction of CO2 to Formate by an Iron Schiff Base Complex
Nichols, Asa W.,Chatterjee, Sayanti,Sabat, Michal,MacHan, Charles W.
supporting information, p. 2111 - 2121 (2018/02/27)
The synthesis, structural characterization, and reactivity of an iron(III) chloride compound of 6,6′-di(3,5-di-tert-butyl-2-hydroxybenzene)-2,2′-bipyridine (Fe(tbudhbpy)Cl), under electrochemically reducing conditions is reported. In the presence of carbon dioxide (CO2) under anhydrous conditions in N,N-dimethylformamide (DMF), this complex mediates the 2e- reductive disproportionation of two equivalents of CO2 to carbon monoxide (CO) and carbonate (CO32-). Upon addition of phenol (PhOH) as a proton source under CO2 saturation, catalytic current is observed; product analysis from controlled potential electrolysis experiments shows the majority product is formate (68 ± 4% Faradaic efficiency), with H2 as a minor product (30 ± 10% Faradaic efficiency) and minimal CO (1.1 ± 0.3% Faradaic efficiency). On the basis of data obtained from cyclic voltammetry and infrared spectroelectrochemistry (IR-SEC), the release of CO from intermediate Fe carbonyl species is extremely slow and undergoes competitive degradation, limiting the activity and lifetime of this catalyst. Mechanistic studies also indicate the phenolate moieties coordinated to Fe are sensitive to protonation in the reduced state, suggesting the possibility of cooperative pendent proton interactions being involved in CO2 reduction.
Mechanistic Investigations of the Hydrogenolysis of Diaryl Ethers Catalyzed by Nickel Complexes of N-Heterocyclic Carbene Ligands
Saper, Noam I.,Hartwig, John F.
supporting information, p. 17667 - 17676 (2017/12/15)
Recent interest in the valorization of lignin has led to reactions involving the cleavage of strong aromatic C-O bonds. However, few experimental mechanistic studies of these reactions have been published. We report detailed mechanistic analysis of the hydrogenolysis of diaryl ethers catalyzed by the combination of Ni(COD)2 (COD = 1,5-cyclooctadiene) and an N-heterocyclic carbene (NHC). Experiments on the catalytic reaction indicated that NaOt-Bu was necessary for catalysis, but kinetic analysis showed that the base is not involved in the rate-limiting C-O bond cleavage. The resting state of the catalyst is an NHC-Ni(η6-arene) complex. Substitution of the coordinated solvent with diaryl ether allowed isolation of a diaryl ether-bound Ni complex. Rate-limiting C-O bond cleavage occurs to generate a three-coordinate product of oxidative addition, a metallacyclic version of which has been prepared independently. Stoichiometric studies show that arene and phenol products are released following reaction with H2. NaOt-Bu was found to deprotonate the phenol product and to prevent formation of inactive NiI dimers.
