88-67-5Relevant articles and documents
Perfluoroalkyl Cobaloximes: Preparation Using Hypervalent Iodine Reagents, Molecular Structures, Thermal and Photochemical Reactivity
Liebing, Phil,Oehler, Florian,Wagner, Mona,Tripet, Pascal F.,Togni, Antonio
, p. 570 - 583 (2018)
Treatment of cobaloximes(II), [Co(Hdmg)2(L)2] (Hdmg = dimethylglyoximate, L = neutral ligand), with perfluoroalkyl iodane reagents leads to the formation of perfluoroalkyl cobaloximes(III), [CoRF(Hdmg)2(L)] (RF = CF3, C2F5, n-C3F7, CF2CF2Ph; L = Py, NH3, MeNH2, PhNH2, MeOH). The synthetic protocol can be significantly simplified to a one-pot procedure starting from cobalt(II) acetate-tetrahydrate. The products have been fully characterized by NMR, IR, and UV/vis spectroscopy as well as single-crystal X-ray diffraction, and the thermal and photochemical reactivity has been studied. According to the Co-L distances in the crystal, the trans influence of the RF- ligands can be rated as C2F5- ≈ n-C3F7- 2CF2Ph- ≈ CF3- 3-. The thermal decomposition of the complexes is different from that of nonfluorinated analogues, probably including perfluoroalkylation of an Hdmg- ligand as the initial step. In the CF3 complexes, the Co-C bond is very resistant against photolysis, but the ligand L is readily exchanged by MeOH upon exposure to blue light. In the complexes with longer RF chains, the Co-C bond is more readily cleaved, and the product distribution depends strongly on the presence of O2. Thus, the alkane RFH is the main product under exclusion of O2, while a fluorinated methyl ester and HF are formed in a methanol solution exposed to air.
Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
, p. 167 - 175 (2021/03/19)
The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
Efficiency of lithium cations in hydrolysis reactions of esters in aqueous tetrahydrofuran
Harada, Yumi,Hayashi, Kazuhiko,Ichimaru, Yoshimi,Imai, Masanori,Kojima, Yuki,Maeda, Azusa,Nakayama, Kanae,Sugiura, Kirara
, p. 581 - 594 (2021/06/06)
Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
N-Alkenylation of hydroxamic acid derivatives with ethynyl benziodoxolone to synthesizecis-enamides through vinyl benziodoxolones
Shimbo, Daisuke,Maruyama, Toshifumi,Tada, Norihiro,Itoh, Akichika
supporting information, p. 2442 - 2447 (2021/04/02)
The stereoselective synthesis ofcis-β-N-alkoxyamidevinyl benziodoxolones (cis-β-N-RO-amide-VBXs) fromO-alkyl hydroxamic acids in the presence of an ethynyl benziodoxolone-acetonitrile complex (EBX-MeCN) is reported herein. The reaction was performed under mild conditions including an aqueous solvent, a mild base, and room temperature. The reaction tolerated variousO-alkyl hydroxamic acids derived from carboxylic acids, such as amino acids, pharmaceuticals, and natural products. Vinyl dideuteratedcis-β-N-MeO-amide-VBXs were also synthesized using deuterium oxide as the deuterium source. Valine-derivedcis-β-N-MeO-amide-VBX was stereospecifically derivatized to hydroxamic acid-derivedcis-enamides without the loss of stereoselectivity or reduction in the deuterium/hydrogen ratio.
Mechanistic Investigation of the Iron-Catalyzed Azidation of Alkyl C(sp3)-H Bonds with Zhdankin’s λ3-Azidoiodane
Chatterjee, Ruchira,Day, Craig S.,Fawcett, Alexander,Hartwig, John F.
supporting information, p. 16184 - 16196 (2021/10/12)
An in-depth study of the mechanism of the azidation of C(sp3)-H bonds with Zhdankin’s λ3-azidoiodane reagent catalyzed by iron(II)(pybox) complexes is reported. Previously, it was shown that tertiary and benzylic C(sp3)-H bonds of a range of complex molecules underwent highly site-selective azidation by reaction with a λ3-azidoiodane reagent and an iron(II)(pybox) catalyst under mild conditions. However, the mechanism of this reaction was unclear. Here, a series of mechanistic experiments are presented that reveal critical features responsible for the high selectivity and broad scope of this reaction. These experiments demonstrate the ability of the λ3-azidoiodane reagent to undergo I-N bond homolysis under mild conditions to form λ2-iodanyl and azidyl radicals that undergo highly site-selective and rate-limiting abstraction of a hydrogen atom from the substrate. The resultant alkyl radical then combines rapidly with a resting state iron(III)-azide complex, which is generated by the reaction of the λ3-azidoiodane with the iron(II)(pybox) complex, to form the C(sp3)-N3bond. This mechanism is supported by the independent synthesis of well-defined iron complexes characterized by cyclic voltammetry, X-ray diffraction, and EPR spectroscopy, and by the reaction of the iron complexes with alkanes and the λ3-azidoiodane. Reaction monitoring and kinetic studies further reveal an unusual effect of the catalyst on the rate of formation of product and consumption of reactants and suggest a blueprint for the development of new processes leading to late-stage functionalization of C(sp3)-H bonds.
Togni-II Reagent Mediated Selective Hydrotrifluoromethylation and Hydrothiolation of Alkenes?
Teng, Shuang,Meng, Lingkui,Xu, Bingbing,Tu, Guangsheng,Wu, Peng,Liao, Zhiwen,Tan, Yulin,Guo, Jian,Zeng, Jing,Wan, Qian
supporting information, p. 3429 - 3434 (2021/11/08)
Based on the redox reactions of Togni-II reagent and thiols, a thiol-tuned selective functionalization of unactivated olefins was disclosed. In combination with aryl thiols, stoichiometric amount of Togni-II reagent prompted a hydrotrifluoromethylation of alkenes, in which, aryl thiols played as reductant and hydrogen source; while by utilization of alkyl thiols, catalytic amount of Togni-II reagent initiated thiol-ene and thiol-yne reactions. The reported applications are characterized by their operational simplicity and wide functional group tolerance.
Palladium Supported on Silk Fibroin for Suzuki–Miyaura Cross-Coupling Reactions
Albano, Gianluigi,Farinola, Gianluca M.,Lo Presti, Marco,Milella, Antonella,Omenetto, Fiorenzo G.,Rizzo, Giorgio
supporting information, p. 6992 - 6996 (2020/11/30)
Silk fibroin supported Pd (Pd/SF) has been prepared and used as catalyst in Suzuki–Miyaura cross-coupling reactions in water/ethanol (4:1 v/v) mixture. The reactions proceed rapidly with aryl iodides and boronic acids with different electronic properties using low metal loading (0.38 mol-%). Pd/SF exhibits better recyclability compared to other biopolymer-supported Pd catalysts, up to nineteen cycles without loss of activity.
IrIII-Catalyzed Selective ortho-Monoiodination of Benzoic Acids with Unbiased C?H Bonds
Weis, Erik,Johansson, Magnus J.,Martín-Matute, Belén
supporting information, p. 10185 - 10190 (2020/07/31)
An iridium-catalyzed selective ortho-monoiodination of benzoic acids with two equivalent C?H bonds is presented. A wide range of electron-rich and electron-poor substrates undergo the reaction under mild conditions, with >20:1 mono/di selectivity. Importantly, the C?H iodination occurs selectively ortho to the carboxylic acid moiety in substrates bearing competing coordinating directing groups. The reaction is performed at room temperature and no inert atmosphere or exclusion of moisture is required. Mechanistic investigations revealed a substrate-dependent reversible C?H activation/protodemetalation step, a substrate-dependent turnover-limiting step, and the crucial role of the AgI additive in the deactivation of the iodination product towards further reaction.
Direct Intermolecular Anti-Markovnikov Hydroazidation of Unactivated Olefins
Li, Hongze,Shen, Shou-Jie,Zhu, Cheng-Liang,Xu, Hao
supporting information, p. 9415 - 9421 (2019/06/21)
We herein report a direct intermolecular anti-Markovnikov hydroazidation method for unactivated olefins, which is promoted by a catalytic amount of bench-stable benziodoxole at ambient temperature. This method facilitates previously difficult, direct addition of hydrazoic acid across a wide variety of unactivated olefins in both complex molecules and unfunctionalized commodity chemicals. It conveniently fills a synthetic chemistry gap of existing olefin hydroazidation procedures, and thereby provides a valuable tool for azido-group labeling in organic synthesis and chemical biology studies.
Iodide as a Nucleophilic Trigger in Aryne Three-Component Coupling for the Synthesis of 2-Iodobenzyl Alcohols
Bhattacharjee, Subrata,Guin, Avishek,Gaykar, Rahul N.,Biju, Akkattu T.
supporting information, p. 4383 - 4387 (2019/06/08)
The synthetic potential of KI as the iodide source in aryne three-component coupling has been demonstrated using aldehydes as the third component. This mild and transition-metal-free coupling reaction allowed the straightforward synthesis of 2-iodobenzyl alcohols in moderate to good yields with good functional group compatibility. Moreover, KBr and KCl could be used as the nucleophilic trigger in this aryne multicomponent coupling (MCC) and N-methylisatin and CO2 could be used as the electrophilic third components.
