2875-19-6Relevant articles and documents
Synthesis and reactivity of the fluoro complex trans -[Pd(F)(4-C 5NF4)(iPr2PCH2CH 2OCH3)2]: C-F bond formation and catalytic C-F bond activation reactions
Breyer, David,Braun, Thomas,Klaering, Paul
, p. 1417 - 1424 (2012)
The reaction of [Pd(Me)2(tmeda)] (tmeda = N,N,N′,N′- tetramethylethylendiamine) with the phosphine iPr2PCH 2CH2OCH3 resulted in the formation of the palladium(0) complex [Pd(iPr2PCH2CH 2OCH3)2] (1). Treatment of 1 with pentafluoropyridine at room temperature yielded the C-F activation product trans-[Pd(F)(4-C5NF4)(iPr2PCH 2CH2OCH3)2] (2). The triflato and bromo complexes trans-[Pd(OTf)(4-C5NF4)( iPr2PCH2CH2OCH3) 2] (4) and trans-[Pd(Br)(4-C5NF4)( iPr2PCH2CH2OCH3) 2] (5) could be prepared on reaction of complex 2 with EtOTf or 3-bromopropene, respectively. Treatment of 2 with Me3SiCl or HBpin (HBpin = 4,4,5,5-tetramethyl-1,3,2-dioxaborolane, pinacolborane) effects the formation of trans-[Pd(Cl)(4-C5NF4)(iPr 2PCH2CH2OCH3)2] (6) and trans-[Pd(H)(4-C5NF4)(iPr2PCH 2CH2OCH3)2] (7). In catalytic experiments pentafluoropyridine could be converted into the 4-aryl- tetrafluoropyridines (8, aryl = Ph; 9, aryl = Tol) and into 2,3,5,6- tetrafluoropyridine in the presence of the boronic acids PhB(OH)2, TolB(OH)2, or HBpin when 5 mol % of 2 is employed as catalyst.
Synthesis, Characterization, and Thermal Properties of Fluoropyridyl-Functionalized Siloxanes of Diverse Polymeric Architectures
Stewart, Kevin A.,Shuster, Dylan,Leising, Maria,Coolidge, Isaac,Lee, Erica,Stevens, Charles,Peloquin, Andrew J.,Kure, Daniel,Jennings, Abby R.,Iacono, Scott T.
, p. 4871 - 4879 (2021)
High-temperature linear fluoropyridyl silicone-based oils and network elastomers were prepared via hydrosilylation with multifunctional perfluoropyridine (PFP)-based monomers possessing terminally reactive alkenes. Monomers with varying degrees of functionalization were prepared in a scalable manner and in high purity via the facile, regio-selective, nucleophilic aromatic substitution (SNAr) of PFP in good isolated yields. These multi-reactive monomers were polymerized via Pt-catalyzed hydrosilylation with hydride-terminated polydimethylsiloxanes (H-PDMSs) possessing varying degrees of polymerization and cross-linked with the highly functionalized octadimethylhydrosilyl cubic siloxane. These resulting polymers of varying architecture possessed exceptional thermal stability with no onset of degradation up to 430 °C and char yields as high as 62%, under inert pyrolysis conditions when modified with cubic siloxane. Furthermore, by nature of the aliphatic or aromatic content, programmable glass transition temperatures were achieved from these elastomeric materials. Finally, the linear 3,5,6-fluoropyridine PDMS systems demonstrated the ability to undergo regio-controlled post-functionalization via SNAr with 4-bromophenol, allowing access to silicone oils with potentially tailorable properties for desired applications.
Dual Photoredox-/Palladium-Catalyzed Cross-Electrophile Couplings of Polyfluoroarenes with Aryl Halides and Triflates
Qin, Jian,Zhu, Shengqing,Chu, Lingling
supporting information, p. 2246 - 2252 (2021/04/02)
A visible-light photoredox-/Pd-catalyzed cross-electrophile arylation of polyfluoroarenes with aryl halides and triflates in the presence of dialkylamines is reported for the first time. This synergistic protocol affords access to a series of fluorodiaryls from easily available starting materials under mild and operationally simple conditions. A series of mechanistic experiments, including the stoichiometric reactions of a ligated (aryl)Pd complex, Stern-Volmer fluorescence quenching studies, cyclic voltammetry studies, and UV-vis spectroscopy, were performed to elucidate the potential catalytic pathway in this synergistic process.
Transition-Metal-Free Catalytic Hydrodefluorination of Polyfluoroarenes by Concerted Nucleophilic Aromatic Substitution with a Hydrosilicate
Kikushima, Kotaro,Grellier, Mary,Ohashi, Masato,Ogoshi, Sensuke
supporting information, p. 16191 - 16196 (2017/11/27)
A transition-metal-free catalytic hydrodefluorination (HDF) reaction of polyfluoroarenes is described. The reaction involves direct hydride transfer from a hydrosilicate as the key intermediate, which is generated from a hydrosilane and a fluoride salt. The eliminated fluoride regenerates the hydrosilicate to complete the catalytic cycle. Dispersion-corrected DFT calculations indicated that the HDF reaction proceeds through a concerted nucleophilic aromatic substitution (CSNAr) process.
