358-43-0Relevant articles and documents
Redox-state dependent activation of silanes and ammonia with reverse polarity (PCcarbeneP)Ni complexes: electrophilic vs. nucleophilic carbenes
LaPierre, Etienne A.,Piers, Warren E.,Gendy, Chris
, p. 16789 - 16797 (2018)
A rigidified PCalkylP ligand allowed for the synthesis and characterization of cationic and radical PCCarbeneP nickel complexes in which the carbene anchor of the pincer framework is electrophilic rather than nucleophilic. Alpha-hydride abstraction from a (PCalkylP)nickel halide complex readily leads to the cationic carbene complex, which furnishes the radical carbene complex by one electron reduction. The reactivity of these reverse polarity carbene complexes towards small molecules (H2, CO, CO2, R3SiH, NH3) reveals different modes of activation when compared to previously reported nucleophilic nickel carbene complexes, and a clear dependence on the redox state of the complex. For H2, CO and CO2, no reaction is observed, but silanes react via hydride transfer and formation of solvated silylium ions. Ammonia is activated in a novel way, wherein it coordinates the carbene carbon and is deprotonated to form a robust C-N bond. This is not only a rare example of ammonia activation by a first row transition metal but also evidence of the intermediacy of group 10 carbenes in direct C-N bond forming reactions.
Activation of SF6 at a Xantphos-Type Rhodium Complex
Wozniak, Martin,Braun, Thomas,Ahrens, Mike,Braun-Cula, Beatrice,Wittwer, Philipp,Herrmann, Roy,Laubenstein, Reik
, p. 821 - 828 (2018)
As a rather inert gas, sulfur hexafluoride is still used as a dielectric in high-voltage power applications despite its high global warming potential. Its activation at transition metal complexes has been reported, but the fate of the sulfur-containing products is often unknown. The activation of SF6 at [Rh(H){tBuxanPOP}] (tBuxanPOP = 9,9-dimethyl-4,5-bis(ditert-butylphosphino)xanthene) at room temperature leads to the generation of the bifluorido complex [Rh(FHF){tBuxanPOP}]. A subsequent regeneration of [Rh(H){tBuxanPOP}] completes a cyclic process for the degradation of SF6. Furthermore, the SF6 activation at [Rh(H){tBuxanPOP}] in the presence of triethylsilane as a hydrogen source is described, which leads to the formation of the fluorido complex [Rh(F)2(H){tBuxanPOP}] as well as [Rh(SH){tBuxanPOP}] and S(SiEt3)2 as sulfur-containing products.
Synthesis of bis(trifluoromethyl)alkylated trisubstituted alkenes via highly regioselective catalyzed hydrosilylation reaction of hexafluoro-2-butyne and their reactivity
Filatov, Andrey A.,Jackson, Andrew,Kirij, Nataliia V.,Peng, Sheng,Yagupolskii, Yurii L.
, (2021/11/24)
Hydrosilylation reaction of hexafluoro-2-butyne 1 (HFB) with various silanes in the presence of a catalytic amount of transition-metal-catalysts was investigated. The reaction of HFB gave the corresponding bis(trifluoromethyl)containing vinylsilanes in an excellent regioselective manner in high yields. Treatment of the resulting vinylsilanes with various aldehydes and ketones in the presence of fluoride ion sources afforded the coupling products in moderate yields.
Bis(perfluoropinacolato)silane: A Neutral Silane Lewis Superacid Activates Si?F Bonds
Greb, Lutz,Hanusch, Franziska,Inoue, Shigeyoshi,Thorwart, Thadd?us,Tschernuth, Florian S.
supporting information, p. 25799 - 25803 (2021/11/09)
Despite the earth abundance and easy availability of silicon, only few examples of isolable neutral silicon centered Lewis superacids are precedent in the literature. To approach the general drawbacks of limited solubility and unselective deactivation pathways, we introduce a Lewis superacid, based on perfluorinated pinacol substituents. The compound is easily synthesized on a gram-scale as the corresponding acetonitrile mono-adduct 1?(MeCN) and was fully characterized, including single crystal X-ray diffraction analysis (SC-XRD) and state-of-the-art computations. Lewis acidity investigations by the Gutmann-Beckett method and fluoride abstraction experiments indicate a Lewis superacidic nature. The challenging Si?F bond activation of Et3SiF is realized and promising catalytic properties are demonstrated, consolidating the potential applicability of silicon centered Lewis acids in synthetic catalysis.
Visible-light photoredox-catalyzed selective carboxylation of C(sp3)?F bonds with CO2
Bo, Zhi-Yu,Chen, Lin,Gao, Tian-Yu,Jing, Ke,Lan, Yu,Liu, Shi-Han,Luo, Shu-Ping,Yan, Si-Shun,Yu, Bo,Yu, Da-Gang
supporting information, p. 3099 - 3113 (2021/11/16)
It is highly attractive and challenging to utilize carbon dioxide (CO2), because of its inertness, as a nontoxic and sustainable C1 source in the synthesis of valuable compounds. Here, we report a novel selective carboxylation of C(sp3)?F bonds with CO2 via visible-light photoredox catalysis. A variety of mono-, di-, and trifluoroalkylarenes as well as α,α-difluorocarboxylic esters and amides undergo such reactions to give important aryl acetic acids and α-fluorocarboxylic acids, including several drugs and analogs, under mild conditions. Notably, mechanistic studies and DFT calculations demonstrate the dual role of CO2 as an electron carrier and electrophile during this transformation. The fluorinated substrates would undergo single-electron reduction by electron-rich CO2 radical anions, which are generated in situ from CO2 via sequential hydride-transfer reduction and hydrogen-atom-transfer processes. We anticipate our finding to be a starting point for more challenging CO2 utilization with inert substrates, including lignin and other biomass.
Isolable Silicon-Based Polycations with Lewis Superacidity
Hermannsdorfer, André,Driess, Matthias
supporting information, p. 23132 - 23136 (2020/10/19)
Molecular silicon polycations of the types R2Si2+ and RSi3+ (R=H, organic groups) are elusive Lewis superacids and currently unknown in the condensed phase. Here, we report the synthesis of a series of isolable terpyridine-stabilized R2Si2+ and RSi3+ complexes, [R2Si(terpy)]2+ (R=Ph 12+; R2=C12H8 22+, (CH2)3 32+) and [RSi(terpy)]3+ (R=Ph 43+, cyclohexyl 53+, m-xylyl 63+), in form of their triflate salts. The stabilization of the latter is achieved through higher coordination and to the expense of reduced fluoride-ion affinities, but a significant level of Lewis superacidity is nonetheless retained as verified by theory and experiment. The complexes activate C(sp3)?F bonds, as showcased by stoichiometric fluoride abstraction from 1-fluoroadamantane (AdF) and the catalytic hydrodefluorination of AdF. The formation of the crystalline adducts [2(F)]+ and [5(H)]2+ documents in particular the high reactivity towards fluoride and hydride donors.
PROCESS FOR PRODUCING SULFONIC ACID GROUP-CONTAINING MONOMER
-
, (2021/01/22)
The present disclosure is directed to provide a process capable of producing a sulfonic acid group-containing monomer in a good yield, which can be used as a raw material of fluorine-based polymer electrolytes, such as membranes for fuel cells, catalyst binder polymers for fuel cells, and membranes for chlor-alkali electrolysis. A process for producing a sulfonic acid group-containing monomer represented by the general formula (3) includes the step of mixing and stirring a cyclic compound represented by the general formula (1) and a silanol compound represented by the general formula (2).
Ligand-Controlled Regiodivergent Silylation of Allylic Alcohols by Ni/Cu Catalysis for the Synthesis of Functionalized Allylsilanes
Gan, Yi,Xu, Wei,Liu, Yuanhong
supporting information, p. 9652 - 9657 (2019/11/28)
The first Ni/Cu-catalyzed regiodivergent synthesis of allylsilanes directly from allylic alcohols through modulating the steric and electronic properties of the ligands on the nickel catalyst has been developed. Good yields and excellent selectivity were obtained regardless of whether linear or α-branched allylic alcohols were utilized. Mechanistic studies indicate that an allyloxyboronate species is formed during the reaction, which likely serves as an activated intermediate toward the oxidative addition of the C(allyl)-O bond.
Axially Chiral, Electrophilic Fluorophosphonium Cations: Synthesis, Lewis Acidity, and Reactivity in the Hydrosilylation of Ketones
Süsse, Lars,Lafortune, James H. W.,Stephan, Douglas W.,Oestreich, Martin
supporting information, p. 712 - 721 (2019/02/17)
Axially chiral [(C6F5)3PF][B(C6F5)4] analogues based on dihydrophosphepines with a binaphthyl backbone were prepared and structurally characterized by X-ray diffraction analysis. Computational calculations of FIA and GEI values attest that these new fluorophosphonium cations have a higher Lewis acidity compared to the ubiquitous B(C6F5)3. Furthermore, application of these highly electrophilic compounds in the catalytic hydrosilylation of ketones and an investigation of the mechanism lead to a refined picture of the role of highly electrophilic fluorophosphonium cations.
Catalytic Hydrodefluorination of C?F Bonds by an Air-Stable PIII Lewis Acid
Chitnis, Saurabh S.,Krischer, Felix,Stephan, Douglas W.
, p. 6543 - 6546 (2018/04/26)
Catalytic hydrodefluorination (HDF) of unactivated fluoroalkanes or CF3-substituted aryl species is performed using the PIII Lewis acids, [(bipy)PPh]2+ (12+) and [(terpy)PPh]2+ (22+) under
