334-68-9Relevant academic research and scientific papers
Synthesis of Alkyl Fluorides by Silver-Catalyzed Radical Decarboxylative Fluorination of Cesium Oxalates
Brioche, Julien,Vincent, émilie
, p. 2421 - 2430 (2021/06/25)
A combination of silver nitrate (AgNO3) catalyst and Selectfluor was found to perform radical deoxyfluorination of cesium oxalates derived from corresponding alcohols. The reaction tolerates a wide range of functional groups and provides preferentially access to tertiary alkyl fluorides.
Photoredox-catalyzed deoxyfluorination of activated alcohols with Selectfluor
González-Esguevillas, María,Miró, Javier,Jeffrey, Jenna L.,MacMillan, David W.C.
supporting information, p. 4222 - 4227 (2019/06/13)
Herein we disclose a deoxyfluorination of alcohols with an electrophilic fluorine source via visible-light photoredox catalysis. This radical-mediated C–F coupling is capable of fluorinating secondary and tertiary alcohols efficiently, complementing previously reported nucleophilic deoxyfluorination protocols.
Hypervalent Iodine(III)-Mediated Oxidative Fluorination of Alkylsilanes by Fluoride Ions
Xu, Peng,Wang, Feng,Fan, Guilan,Xu, Xiufang,Tang, Pingping
, p. 1101 - 1104 (2017/01/18)
The first example of a hypervalent iodine(III)-mediated oxidative fluorination of alkylsilanes by fluoride ions without the use of transition metals is demonstrated. This reaction is operationally simple, scalable, and proceeds under mild reaction conditions. Mechanistic studies suggest the involvement of a single-electron transfer resulting from the interaction of an organopentafluorosilicate and aryliodonium difluoride, which were generated in situ from the corresponding alkylsilane and iodosobenzene, respectively, in the presence of fluoride ions.
Mechanism of Copper-Catalyzed Hydroalkylation of Alkynes: An Unexpected Role of Dinuclear Copper Complexes
Suess, Alison M.,Uehling, Mycah R.,Kaminsky, Werner,Lalic, Gojko
supporting information, p. 7747 - 7753 (2015/06/30)
This article describes a mechanistic study of copper-catalyzed hydroalkylation of terminal alkynes. Relying on the established chemistry of N-heterocyclic carbene copper hydride (NHCCuH) complexes, we previously proposed that the hydroalkylation reaction proceeds by hydrocupration of an alkyne by NHCCuH followed by alkylation of the resulting alkenylcopper intermediate by an alkyl triflate. NHCCuH is regenerated from NHCCuOTf through substitution with CsF followed by transmetalation with silane. According to this proposal, NHCCuH must react with an alkyne faster than with an alkyl triflate to avoid reduction of the alkyl triflate. However, we have determined that NHCCuH reacts with alkyl triflates significantly faster than with terminal alkynes, strongly suggesting that the previously proposed mechanism is incorrect. Additionally, we have found that NHCCuOTf rapidly traps NHCCuX (X = F, H, alkenyl) complexes to produce (NHCCu)2(μ-X)(OTf) (X = F, H, alkenyl) complexes. In this article, we propose a new mechanism for hydroalkylation of alkynes that features dinuclear (NHCCu)2(μ-H)(OTf) (X = F, H, alkenyl) complexes as key catalytic intermediates. The results of our study establish feasible pathways for the formation of these intermediates, their ability to participate in the elementary steps of the proposed catalytic cycle, and their ability to serve as competent catalysts in the hydroalkylation reaction. We also provide evidence that the unusual reactivity of the dinuclear complexes is responsible for efficient hydroalkylation of alkynes without concomitant side reactions of the highly reactive alkyl triflates. (Figure Presented).
Catalytic nucleophilic fluorination by an imidazolium ionic liquid possessing trialkylphosphine oxide functionality
Paramanik, Minakshmi,Singh, Rekha,Mukhopadhyay, Sulekha,Ghosh, Sunil K.
, p. 47 - 55 (2015/07/15)
Abstract The synthesis of a new alkylmethylimidazolium ionic liquid wherein the alkyl group is functionalized with dihexylphosphine oxide moiety at the terminal position has been achieved in four steps from 1-methylimidazole. This hybrid ionic liquid effectively catalyzed the nucleophilic fluorination of primary alkyl mesylates under mild conditions using CsF as the fluoride source with a faster rate compared to butylmethylimidazolium mesylate. The hybrid catalyst was recycled 5 times without compromising the yield and purity of the product. The nucleophilic fluorination has been used for the synthesis of diethyl 2-(5-fluoropentyl)-2-methyl malonate, a precursor of 18F isotopomer of an apoptosis imaging agent and the protected form of O-(2'-fluoroethyl)-l-tyrosine, a 18F isotopomer of a tumor imaging agent.
Mild copper-catalyzed fluorination of alkyl triflates with potassium fluoride
Dang, Hester,Mailig, Melrose,Lalic, Gojko
supporting information, p. 6473 - 6476 (2014/06/24)
A chemoselective catalytic fluorination of alkyl triflates is described using potassium fluoride as a fluoride source. Excellent yields of the desired alkyl fluorides are obtained after one hour at 45°C using 2 mol% of the copper catalyst. With 10 mol% of the catalyst, full conversion can be achieved in less than 10 minutes at 45°C, and thus makes this procedure potentially suited for the preparation of 18F-labeled PET probes. As a result of the mild reaction conditions, only the substitution products are observed with no evidence of common side reactions, such as elimination. Reported is a preliminary study of the reaction scope, which demonstrates that the fluorination can be performed in the presence of a wide range of functional groups. Evidence suggests an unusual role of the [IPrCuOTf] catalyst as a phase-transfer catalyst and points to [IPrCuF] as the active fluorinating reagent (IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene).
Efficient SN2 fluorination of primary and secondary alkyl bromides by copper(I) fluoride complexes
Liu, Yanpin,Chen, Chaohuang,Li, Huaifeng,Huang, Kuo-Wei,Tan, Jianwei,Weng, Zhiqiang
, p. 6587 - 6592 (2013/12/04)
Copper(I) fluoride complexes ligated by phenanthroline derivatives have been synthesized and structurally characterized by X-ray crystallography. These complexes adopt as either ionic or neutral forms in the solid state, depending on the steric bulkiness of the substituent groups on the phenanthroline ligands. These complexes react with primary and secondary alkyl bromides to produce the corresponding alkyl fluorides in modest to good yields. This new method is compatible with a variety of important functional groups such as ether, thioether, amide, nitrile, methoxyl, hydroxyl, ketone, ester, and heterocycle moieties.
Arylsulfur chlorotetrafluorides as useful fluorinating agents: Deoxo- and dethioxo-fluorinations
Umemoto, Teruo,Singh, Rajendra P.
experimental part, p. 17 - 27 (2012/09/07)
Usage of arylsulfur chlorotetrafluorides 1 as versatile deoxo- and dethioxo-fluorinating agents is described. There have been developed two convenient methods for the in situ preparation of reactive arylsulfur trifluorides 2 from 1. The one is reduction of 1 with a reducer such as pyridine to 2, and the other is disproportionation of 1 with a diaryl disulfide to 2 with evolution of chlorine gas. The latter method is a convenient way to get neat 2 from 1. The in situ prepared 2 fluorinates many kinds of substrates such as alcohols, aldehydes, ketones, diketones, and carboxylic acids to give the corresponding CF, CF2, CF2CF2, and CF 3 compounds in high yields. 2 also fluorinates various sulfur compounds including CS groups to give CF2, OCF2, CF 3, and OCF3 compounds in high yields. Reactions of 2 with diols or bis(trimethylsilyl) derivatives of diols or amino alcohols provided the corresponding deoxofluoro-arylsulfinylation products in high yields. In addition, it has been found that chlorotetrafluorides 1 directly and effectively react with the sulfur compounds to give the corresponding fluoro compounds in high yields. Since they are the intermediates for the production of industrially useful arylsulfur pentafluorides, arylsulfur chlorotetrafluorides 1, in particular, phenylsulfur chlorotetrafluoride (1a) are expected to find use as inexpensive and versatile deoxo- and dethioxo-fluorinating agents for the preparation of many organofluoro compounds.
Discovery of 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride as a deoxofluorinating agent with high thermal stability as well as unusual resistance to aqueous hydrolysis, and its diverse fluorination capabilities including deoxofluoro-arylsulfinylation with high stereoselectivity
Umemoto, Teruo,Singh, Rajendra P.,Xu, Yong,Saito, Norimichi
supporting information; experimental part, p. 18199 - 18205 (2011/03/18)
Versatile, safe, shelf-stable, and easy-to-handle fluorinating agents are strongly desired in both academic and industrial arenas, since fluorinated compounds have attracted considerable interest in many areas, such as drug discovery, due to the unique effects of fluorine atoms when incorporated into molecules. This article describes the synthesis, properties, and reactivity of many substituted and thermally stable phenylsulfur trifluorides, in particular, 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride (Fluolead, 1k), as a crystalline solid having surprisingly high stability on contact with water and superior utility as a deoxofluorinating agent compared to current reagents, such as DAST and its analogues. The roles of substiuents on 1k in thermal and hydrolytic stability, fluorination reactivity, and the high-yield fluorination mechanism it undergoes have been clarified. In addition to fluorinations of alcohols, aldehydes, and enolizable ketones, 1k smoothly converts non-enolizable carbonyls to CF2 groups, and carboxylic groups to CF3 groups, in high yields. 1k also converts C(=S) and CH3SC(=S)O groups to CF2 and CF3O groups, respectively, in high yields. In addition, 1k effects highly stereoselective deoxofluoro-arylsulfinylation of diols and amino alcohols to give fluoroalkyl arylsulfinates and arylsulfinamides, with complete inversion of configuration at fluorine and the simultaneous, selective formation of one conformational isomer at the sulfoxide sulfur atom. Considering the unique and diverse properties, relative safety, and ease of handling of 1k in addition to its convenient synthesis, it is expected to find considerable use as a novel fluorinating agent in both academic and industrial arenas.
FLUOROAMINE HAVING PERFLUOROALKYL GROUP, PROCESS FOR PRODUCING THE SAME, METHOD OF FLUORINATION THEREWITH, AND METHOD OF RECOVERING AMIDE HAVING PERFLUOROALKYL GROUP
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Page/Page column 8, (2009/03/07)
Provided are a fluorous-tag-introduced fluoroamine of a general formula (I), its production method, a method of fluorination of a substrate having functional group containing oxygen with the fluoroamine serving as a fluorinating agent, and a method of recovering a fluorous-tag-introduced amide after the fluorination. The fluoroamine and its production method, as well as the fluorination method with the fluoroamine and the method of recovery of a fluorous-tag-introduced amide are ecological and advantageous in industrial use, as the load for separating and collecting the product after the fluorination with the fluoroamine serving as a fluorinating agent is small. (In the formula, R0 is an alkyl group or an aryl group having substituent(s) of Rf-(CH2)m-; Rf is a perfluoroalkyl group; m is from 0 to 2; R1 and R2 each are an alkyl group or an aryl group.)
