- Ullmann reaction optimization within bitolyl and decafluorobiphenyl synthesis
-
This article describes the investigation of the cross-coupling Ullman's reaction of aryl halides under various conditions to find optimal scalable method of biaryl synthesis and the development of preparative methods of synthesizing 3,3'-bitolyl and perfluorobipfenyl, which are valuable semi-products of organic synthesis.
- Kolotaev,Razinov,Khachatryan
-
-
Read Online
- Intriguing Behavior of an Apparently Simple Coupling Promoter Ligand, PPh2(p-C6H4-C6F5), in Their Pd Complexes
-
Ligand PPh2(p-C6H4-C6F5), LHF, is an example of monodentate biphenyl phosphine that allows for cis coordination of two phosphines to Pd, as in complex cis-[PdPf2Pd(LHF)2] (A) (Pf = C6F5). At 25 °C, complex A undergoes easy reductive elimination to decafluorobiphenyl and, competitively, isomerizes to trans-[Pd(C6F5)2Pd(LHF)2] via functionally three-coordinate intermediates cis-[PdPf2(LHF)(S)] with the fourth position empty or weakly protected (S= THF, OH2, or π-aryl). Unexpectedly, the direct reductive C6F5-C6F5 elimination is faster from the four-coordinate complex A than from the intermediates with only one strong LHF. The reason for this is that two cis LHF ligands play the role of a chelate with a large bite angle and some tetrahedral distortion. As a matter of fact, using LHF in excess (Pd:L ? 1:2), a Pf-Pf coupling barrier ΔG?Pf-Pf = 23.1 kcal·mol-1 is measured, which ranks its efficiency for coupling and formation of the corresponding Pd0 catalyst as better than XantPhos or PhPEWO-F and about the same as tBuBrettPhos. On the other hand, complex (μ-Cl)2[Pd2Rf2(LHF)2] (B) (Rf = C6F3Cl2 = 3,5-dichloro-2,4,6-trifluorophenyl), obtained by reaction of (μ-Cl)2[Pd2Rf2(tht)2] (tht = tetrahydrothiophene) with LHF, presents in the 19F NMR COSY spectrum a very intriguing through-space coupling pattern of the Fortho atoms of the C6F5 group in LHF and the 3-5-C6F3Cl2 group on Pd. The intermittent coupling mechanism proposed is based on the switching of π-π-stacking of C6F5 from one Ph group to another Ph group of LHF, which gives rise to enantiomers at the chiral P atom. Rotation around the P-biphenyl bond under hindered rotation around the C-C6F5 bond produces the intriguing selective coupling observed.
- Pérez-Iglesias, María,Infante, Rebeca,Casares, Juan A.,Espinet, Pablo
-
-
Read Online
- Selective reductive defluorination of dicyclohexyl compounds: Intramolecular coupling reaction by reductive cleavage of C-F bonds
-
Reductive defluorination of perfluoro(dicyclohexyl ether) 1 with benzophenone anion radical in tetrahydrofuran produces perfluoro(dibenzofuran) 2 with a surprising ring-closure, whereas reductive defluorination of perfluoro(dicyclohexyl) 4 under the same conditions gives perfluoro(diphenyl) 6 with no products involving ring-closure.
- Sung, Kuangsen,Lagow, Richard J.
-
-
Read Online
- Pentafluorophenyl transfer: A new group-transfer reaction in organoborate salts
-
Irradiation of isoquinolinium hydroxytris(pentafluorophenyl)borate, 1, and phenanthridium hydroxytris(pentafluorophenyl)borate, 2, in either CH 2Cl2 or CH3CN resulted in C6F 5 transfer to the isoquinolinium and phenanthridium cations, generating 2-methyl-1-(2,3,4,5,6- pentafluorophenyl)-1,2-dihydroisoquinoline, 3, and 2-methyl-1-(2,3,4,5,6-pentafluorophenyl)-1,2-dihydrophenanthridine, 4, respectively. In addition, photogeneration of H2O·B(C 6F5)3 resulted from 1. Photogeneration of C6F5-C6F4H from HO-B(C 6F5)3- and of C6H 5-C6F4H from C6H5- B(C6F5)3- was discovered.
- Hewavitharanage, Priyadarshine,Danilov, Evgeny O.,Neckers, Douglas C.
-
-
Read Online
- Convenient Synthesis of Symmetrical Polyfluorinated Diphenyl Sulfides
-
Abstract: Thermal properties of decafluorodiphenyl disulfide in the pure state and in the presence of copper and iron metals have been studied. A procedure has been proposed for the synthesis of symmetrical poly-fluorinated diaryl sulfides from diaryl dis
- Bredikhin, R. A.,Maksimov, A. M.,Nikul’shin, P. V.,Platonov, V. E.
-
p. 1921 - 1930
(2022/01/24)
-
- Selective synthesis of fluorinated biaryls by [MCl2(PhPEWO-F)] (M = Ni, Pd) catalysed Negishi cross-coupling
-
Highly selective cross-couplings to polyfluorinated assymmetric biaryls, including the symmetric biaryl C6F5-C6F5, are achieved at relatively low temperature (80 °C) and in short times using [MCl2(PhP
- Espinet, Pablo,Ponce-De-León, Jaime
-
supporting information
p. 10875 - 10878
(2021/10/22)
-
- Ranking Ligands by Their Ability to Ease (C6F5)2NiIIL → Ni0L + (C6F5)2Coupling versus Hydrolysis: Outstanding Activity of PEWO Ligands
-
The NiII literature complex cis-[Ni(C6F5)2(THF)2] is a synthon of cis-Ni(C6F5)2 that allows us to establish a protocol to measure and compare the ligand effect on the NiII → Ni0 reductive elimination step (coupling), often critical in catalytic processes. Several ligands of different types were submitted to this Ni-meter comparison: Bipyridines, chelating diphosphines, monodentate phosphines, PR2(biaryl) phosphines, and PEWO ligands (phosphines with one potentially chelate electron-withdrawing olefin). Extremely different C6F5-C6F5 coupling rates, ranging from totally inactive (producing stable complexes at room temperature) to those inducing almost instantaneous coupling at 25 °C, were found for the different ligands tested. The PR2(biaryl) ligands, very efficient for coupling in Pd, are slow and inefficient in Ni, and the reason for this difference is examined. In contrast, PEWO type ligands are amazingly efficient and provide the lowest coupling barriers ever observed for NiII complexes; they yield up to 96% C6F5-C6F5 coupling in 5 min at 25 °C (the rest is C6F5H) and 100% coupling with no hydrolysis in 8 h at-22 to-53 °C.
- Ponce-De-León, Jaime,Gioria, Estefania,Martínez-Ilarduya, Jesús M.,Espinet, Pablo
-
supporting information
p. 18287 - 18294
(2020/12/23)
-
- Palladium-Catalyzed Homocoupling of Highly Fluorinated Arylboronates: Studies of the Influence of Strongly vs Weakly Coordinating Solvents on the Reductive Elimination Process
-
C-C reductive elimination from [PdL2(C6F5)2] to form polyfluorinated biaryls has been a challenge for over 50 years. Thus, palladium-catalyzed homocoupling of arylboronates (ArF-Bpin) containing two ortho-fluorine substituents is very difficult, as the reaction typically stops at the [PdL2(ArF)2] stage after two transmetalation steps. The transmetalated complexes cis-[Pd(MeCN)2(C6F5)2] (3a), cis-[Pd(MeCN)2(2,4,6-C6F3H2)2] (3b), and cis-[Pd(MeCN)2(2,6-C6F2H3)2] (3e) have been isolated from the reaction of ArF-Bpin with Pd(OAc)2 in acetonitrile solvent, with no homocoupling observed. However, catalytic homocoupling proceeds smoothly in a "weakly coordinating" arene solvent as long as no ancillary ligands or coordinating solvents are present. DFT computations reveal that the active catalyst formed by arene solvent coordination leads to an overall reduced barrier for the reductive elimination step compared to the formation of stable [PdL2(ArF)2] complexes in the presence of a donor ligand or solvent L.
- Budiman, Yudha P.,Friedrich, Alexandra,Jayaraman, Arumugam,Kerner, Florian,Marder, Todd B.,Radius, Udo
-
supporting information
p. 6036 - 6050
(2020/04/27)
-
- Discovery and mechanistic investigation of Pt-catalyzed oxidative homocoupling of benzene with PhI(OAc)2
-
We present a Pt-catalyzed direct coupling of benzene to biphenyl. This catalytic reaction employs a cyclometalated platinum(ii) complex [PtMe(bhq)(SMe2)] (bhq = benzo[h]quinolate) with PhI(OAc)2 as an oxidant and does not require an acid, a co-catalyst or a solvent. The reaction kinetics and characterization of potential catalytic species are reported. The reaction is first-order in Pt and second-order in benzene, which implicates the second C-H activation step as rate-determining. A Pt(ii)/Pt(iv) catalytic cycle is suggested. The reaction commences by oxidation of the Pt(ii) complex to give the platinum(iv) species [Pt(bhq)(SMe2)(OAc)2](OAc) followed by C-H activation of benzene to afford the intermediate [PtPh(bhq)(SMe2)(OAc)](OAc) concurrently with the release of HOAc. A second benzene molecule reacts similarly to give the diphenyl intermediate [PtPh2(bhq)(SMe2)](OAc). C-C bond forming reductive elimination ensues to regenerate Pt(ii) and complete the catalytic cycle. The proposed mechanism has been examined by DFT computations, which provide support to experimental findings.
- Abu-Omar, Mahdi M.,Nabavizadeh, S. Masoud,Niroomand Hosseini, Fatemeh,Park, Chan,Wu, Guang
-
supporting information
p. 2477 - 2486
(2020/03/05)
-
- E- Z Isomerization of Phosphine-Olefin (PEWO-F4) Ligands Revealed upon PdCl2 Capture: Facts and Mechanism
-
The PEWO phosphines R2P(o-C6H4CH-CHC(O)Ph), R2P(o-C6H2F2CH-CHC(O)Ph), and R2P(o-C6F4CH-CHC(O)Ph) and their P-monodentate complexes trans-[PdCl2(P-monodentate)2] show, in solution and (when available) in the X-ray diffraction structures, an E configuration of the double bond. In contrast, the structures of [PdCl2(P-chelate)] display E and Z configurations. The E/Z isomerization of the latter requires first decoordination of the double bond, which then allows for easy rotation about the electron-deficient double bond. Thus, the E/Z equilibria exist for the free and the P-monodentate complexes as well but are not observed because they are extremely displaced toward the E isomer. Their capture in the form of [PdCl2(P-chelate)], with equilibrium constants on the order Keq ≈ 1-3, allows the two configurations to be observed and isolated. Evaluation of their ability to couple Pf-Pf from cis-[PdPf2(THF)2] (Pf = C6F5) affords values of their ΔG?(Pf-Pf)Pd parameters confirming that higher substitution of H by F produces lower coupling barriers and a double bond that is more electron deficient when it is free and more electron withdrawing when it is coordinated.
- Pe?as-Defrutos, Marconi N.,Vélez, Andrea,Gioria, Estefanía,Espinet, Pablo
-
supporting information
p. 4701 - 4707
(2019/12/24)
-
- Electrochemical instability of highly fluorinated tetraphenyl borates and syntheses of their respective biphenyls
-
Highly fluorinated tetraphenyl borate anions are of importance as weakly coordinating anions in metalorganic reactions. However, at high positive potentials their electrochemical stability in organic solvents is not sufficient. This was investigated by a comprehensive cyclic voltammetry study and can be used synthetically to generate highly fluorinated biphenyls.
- Beil, Sebastian B.,M?hle, Sabine,Enders, Patrick,Waldvogel, Siegfried R.
-
supporting information
p. 6128 - 6131
(2018/06/18)
-
- Three-Coordinate Copper(II) Aryls: Key Intermediates in C-O Bond Formation
-
Copper(II) aryl species are proposed key intermediates in Cu-catalyzed cross-coupling reactions. Novel three-coordinate copper(II) aryls [CuII]-C6F5 supported by ancillary β-diketiminate ligands form in reactions between c
- Kundu, Subrata,Greene, Christine,Williams, Kamille D.,Salvador, Tolani K.,Bertke, Jeffery A.,Cundari, Thomas R.,Warren, Timothy H.
-
p. 9112 - 9115
(2017/07/24)
-
- Carbon-Carbon Bond-Forming Reductive Elimination from Isolated Nickel(III) Complexes
-
This manuscript describes the design, synthesis, characterization, and reactivity studies of organometallic NiIII complexes of general structure TpNiIII(R)(R1) (Tp = tris(pyrazolyl)borate). With appropriate selection of th
- Bour, James R.,Camasso, Nicole M.,Meucci, Elizabeth A.,Kampf, Jeff W.,Canty, Allan J.,Sanford, Melanie S.
-
supporting information
p. 16105 - 16111
(2016/12/22)
-
- Promoting Difficult Carbon–Carbon Couplings: Which Ligand Does Best?
-
A Pd complex, cis-[Pd(C6F5)2(THF)2] (1), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C?C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd0L. Complex 1 ranks the coupling ability of some popular ligands in the order PtBu3>o-TolPEWO-F≈tBuXPhos>P(C6F5)3≈PhPEWO-F>P(o-Tol)3≈THF≈tBuBrettPhos?Xantphos≈PhPEWO-H?PPh3according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈PtBu3≈o-TolPEWO-F>PhPEWO-F>P(C6F5)3?tBuBrettPhos>THF≈P(o-Tol)3>Xantphos>PhPEWO-H?PPh3. This “meter” also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos.
- Gioria, Estefanía,del Pozo, Juan,Martínez-Ilarduya, Jesús M.,Espinet, Pablo
-
supporting information
p. 13276 - 13280
(2016/10/30)
-
- Synthesis of fluorophenyl carbonyl cobalt(I) complexes and decarbonylation of 2,4,5-trifluorobenzaldehyde catalyzed by CoMe(PMe3)4
-
Three fluorophenyl carbonyl cobalt(I) complexes PhF(PMe3)3Co(CO) (1-3) were synthesized by the reaction of fluoro-benzaldehydes with CoMe(PMe3)4 via C-H bond activation and decarbonylation reaction. The dicarbonyl cobalt(I) complex (2,4-F2C6H3)Co(CO)2(PMe3)2 (4) was obtained by reacting of complex 1 with CO. Complex 1 reacted with pentafluorobromobenzene afforded cobalt(II) bromide (2,4-F2C6H3)Co(Br)(PMe3)3 (5) with the formation of perfluorinated diphenyl. The reaction of complex 3 and phenylacetylene delivered the hydrido diethinyl cobalt(III) complex (PhCC)2Co(H)(PMe3)3 (6) with 1,2,4-trifluorobenzene as a byproduct. The molecular structures of 1, 4 and 5 were determined by X-ray diffraction. Furthermore, we found that CoMe(PMe3)4 could be used as a catalyst for the catalytic decarbonylation of 2,4,5-trifluorobenzaldehyde with triethylsilane as a hydrogen source.
- Yuan, Shuo,Sun, Hongjian,Zhang, Shumiao,Li, Xiaoyan
-
p. 100 - 105
(2015/11/03)
-
- Palladium(0) complexes of N-heterocyclic carbene ligands with dangling NMeC=O functionalities: Synthesis, reactivity and application in Mizoroki-Heck reactions
-
Abstract A series of new Pd(0) complexes of N-heterocyclic carbene (NHC) ligands with dangling NMe(CO) functionalities (LMe) is reported, with yields in the range 56-73%. The reactivity of one of the Pd(0) complexes, bearing bulky N-mesityl groups, towards the oxidative addition of pentafluoroiodobenzene was studied, revealing the formation of decafluorobiphenyl, a diiodo Pd(II) NHC complex and an intriguing Pd(II) complex with four carbon-donor ligands coordinated to the metal center. The latter complex contains two new NHC ligands derived from LMe. One of the NHC ligands is a bidentate ligand, resulting from an addition reaction between LMe and the coordinated maleic anhydride. The other NHC ligand is derived from the N-protonation of LMe. A pentafluorophenyl ligand completes the fourth coordination site. A mechanism for the formation of this intriguing Pd(II) complex is proposed. The structures of these two new Pd(II) complexes were established by single-crystal X-ray diffraction studies. The catalytic activities of the new Pd(0) complex with LMe in the Mizoroki-Heck coupling reaction between 4-chloroacetophenone and styrene were compared and they contrast with those reported for the Pd(0) NHC complex with dangling NH(CO) groups (LH).
- Jhou, Yang-Ming,Nandi, Debkumar,Lee, Jhen-Yi,Tzeng, Ru-Jiun,Lee, Hon Man
-
-
- Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki-Miyaura reactions? Relative reactivity of K[4-RC6F4BF3] and the role of silver-assistance in acceleration of transmetallation
-
Small differences in the reactivity of weakly nucleophilic potassium aryltrifluoroborates are revealed in the silver-assisted Pd-catalyzed cross-coupling of K[4-RC6F4BF3] (R = H, Bu, MeO, EtO, PrO, iPrO, BuO, t-BuO, CH2=CHCH2O, PhCH2O, PhCH2CH2O, PhO, F, pyrazol-1-yl, pyrrol-1-yl, and indol-1-yl) with ArX (4-BrC6H4CH3, 4-IC6H4F and 3-IC6H4F). An assumed role of silver(I) compounds AgmY (Y = O, NO3, SO4, BF4, F) consists in polarization of the Pd-X bond in neutral complex ArPdLnX with the generation of the related transition state or formation of [ArPdLn][XAgmY] with a highly electrophilic cation and subsequent transmetallation with the weakly nucleophilic borate. Efficiency of AgmY as a polarizing agent decreases in order Ag2O > AgNO3 ≈ Ag2SO4 > Ag[BF4] > AgF. No clear correlation between the reactivity of K[4-RC6F4BF3] and substituent electron parameters, σI and σR °, of the aryl group 4-RC6F4 was found.
- Bardin, Vadim V.,Shabalin, Anton Yu,Adonin, Nicolay Yu
-
supporting information
p. 608 - 616
(2015/06/08)
-
- A neutral Gold(III)-Boron transmetalation
-
The occurrence of direct transmetalation between gold(III) and boron species during gold-catalyzed cross-coupling reactions has recently become the subject of intense discussion. In this work, we investigate the transmetalation reaction between discrete, stable gold(III) complexes and boron reagents. Interestingly, electron-rich arylboronic acids remain unreactive under neutral conditions, whereas electron-deficient species undergo transmetalation in a highly efficient manner.
- Hofer, Manuel,Gomez-Bengoa, Enrique,Nevado, Cristina
-
supporting information
p. 1328 - 1332
(2014/04/17)
-
- Thermal decomposition of 4-fluorobenzenediazonium perfluoroorganyl(fluoro) borates, [4-FC6H4N2]Y (Y = RFBF 3 (RF = C6F5, C6F 13, trans-C4F9CFCF, cis-C6F 13CFCF, CF3CC) and (C6F13) 2BF2)
-
Heating of the neat salts [4-FC6H4N 2][RFBF3] (RF = C6F 5, C6F13, trans-C4F9CFCF, cis-C6F13CFCF, CF3CC) or in solid mixtures with NaF gives the principal product 1,4-C6F2H4 besides RFBF2 or Na[RFBF3], respectively. Thermolysis of [4-FC6H4N2] [(C6F13)2BF2] in NaF results in 1,4-C6F2H4, Na[BF4], Na[(C 6F13)2BF2], and a new type of product, the isomer Na[C6F13CF(BF3)C 5F11].
- Bardin, Vadim V.,Frohn, Hermann-Josef
-
p. 333 - 338
(2014/01/06)
-
- Cross-coupling of arene-gold(III) complexes
-
The reactivity of electron-deficient arene-gold(III) complexes toward nucleophilic aromatic and heteroaromatic counterparts has been studied. 1-Methylindole proved to be the best reaction partner while trimethoxybenzenes did not react. The ancillary ligand on gold also influenced the reactivity in the order PPh3>PtBu3>IPr. An oxidative cross-coupling starting from the corresponding gold(I) complexes in presence of hypervalent iodide oxidants was also studied.
- Hofer, Manuel,Nevado, Cristina
-
p. 5751 - 5757
(2013/07/11)
-
- Copper-catalyzed dehydrogenative cross-coupling of benzothiazoles with thiazoles and polyfluoroarene
-
A copper-catalyzed dehydrogenative cross-coupling of benzothiazoles with thiazoles and polyfluoroarene under mild reaction conditions is described. This protocol provides a straightforward and operationally simple method for the synthesis of the 2,27prime;-linkage of thiazoles and 2-polyfluoroarylthiazoles of interest in life and material sciences.
- Fan, Shilu,Zhang, Xingang,Chen, Zhao
-
supporting information
p. 4950 - 4953,4
(2020/09/16)
-
- Synthesis and skeletal rearrangements of perfluorinated 4-alkyl- and 4-phenyl-tetralin-1-ones under the action of antimony pentafluoride
-
Heating of perfluorinated 1-methyl- and 1-ethyltetralins with SiO 2 in an SbF5 medium at 100 °C results in perfluoro-4-alkyltetralin-1-ones formation. Perfluoro-4-methyltetralin-1-one, under the action of SbF5 at 180 °C with subsequent treatment of the reaction mixture with water, is converted to perfluoro-3,3-dimethylindan-1- one and perfluoro-3,4-dimethylisochromen-1-one. Perfluoro-4-ethyltetralin-1-one, under similar conditions, forms perfluoro-3-ethyl-3-methylindan-1-one, perfluoro-4-ethyl-3-methylisochromen-1-one and perfluoro-2-methyltetralin. Reaction of perfluorotetralin-1-one with pentafluorobenzene in the presence of SbF5 at 50-55 °C leads to the formation of perfluoro-4- phenyltetralin-1-one, which under the action of SbF5 at 75 °C isomerizes into perfluoro-3-methyl-3-phenylindan-1-one. Heating of the latter with SbF5 at 75-95 °C gives, after treatment of the reaction mixture with water, perfluoro-2-(2-methylphenyl)-3-phenylpropenoic acid and perfluoro-4-methyl-3-phenylisochromen-1-one.
- Zonov, Yaroslav V.,Karpov, Victor M.,Platonov, Vyacheslav E.
-
experimental part
p. 159 - 166
(2012/04/10)
-
- Pd-catalyzed dehydrogenative cross-coupling of polyfluoroarenes with heteroatom-substituted enones
-
The first example of intermolecular regioselective α-arylation of heteroatom-substituted enones with polyfluoroarenes via twofold C-H bond functionalization using a palladium catalyst is reported. This approach provides rapid access to a wide range of α-fluoroarylated enones of interest in life science.
- Chen, Fei,Feng, Zhang,He, Chun-Yang,Wang, Hao-Yang,Guo, Yin-Long,Zhang, Xingang
-
supporting information; experimental part
p. 1176 - 1179
(2012/04/04)
-
- Me3SiCF3/AgF/Cu - A new reagents combination for selective trifluoromethylation of various organic halides by trifluoromethylcopper, CuCF3
-
An alternative copper halide-free route to obtain highly reactive trifluoromethylcopper species has been developed via the reaction of silver fluoride and trimethyl(trifluoromethyl)silane followed by a redox transmetallation with elemental copper. The composition of the reactive intermediate was investigated by means of UV/Vis/NIR, ESR, 19F NMR spectroscopy and ESI mass spectrometry. "Trifluoromethylcopper" prepared by the oxidative transmetallation route exhibits excellent reactivity and selectivity in substitutions of iodine or bromine bond to aromatic or heterocyclic compounds for trifluoromethyl groups without any additional catalyst.
- Kremlev, Mikhail M.,Mushta, Aleksej I.,Tyrra, Wieland,Yagupolskii, Yurii L.,Naumann, Dieter,M?ller, Angela
-
experimental part
p. 67 - 71
(2012/03/10)
-
- Copper-catalyzed direct C-H oxidative trifluoromethylation of heteroarenes
-
This article describes the copper-catalyzed oxidative trifluoromethylation of heteroarenes and highly electron-deficient arenes with CF 3SiMe3 through direct C-H activation. In the presence of catalyst Cu(OAc)2, ligand 1,10-phenanthroline and cobases tert-BuONa/NaOAc, oxidative trifluoromethylation of 1,3,4-oxadiazoles with CF3SiMe3 proceeded smoothly using either air or di-tert-butyl peroxide as an oxidant to give the corresponding trifluoromethylated 1,3,4-oxadiazoles in high yields. Di-tert-butyl peroxide was chosen as the suitable oxidant for oxidative trifluoromethylation of 1,3-azoles and perfluoroarenes. Cu(OH)2 and Ag2CO3 were the best catalyst and oxidant for direct oxidative trifluoromethyaltion of indoles. The optimum reaction conditions enable oxidative trifluoromethylation of a range of heteroarenes that bear numerous functional groups. The prepared trifluoromethylated heteroarenes are of importance in the areas of pharmaceuticals and agrochemicals. The preliminary mechanistic studies of these oxidative trifluoromethylations are also reported.
- Chu, Lingling,Qing, Feng-Ling
-
supporting information; experimental part
p. 1298 - 1304
(2012/02/16)
-
- Synthesis of biaryls by Pd-catalyzed decarboxylative homo- and heterocoupling of substituted benzoic acids
-
By carefully choosing the right substrate ratio, catalyst combination, and base, symmetrical and unsymmetrical biaryls can be readily synthesized through the Pd-catalyzed decarboxylative homo- and heterocoupling of substituted benzoic acids. The reaction gave the desired products in 40-90% yield and is compatible with 2-nitro-, 2-methoxy-, 2-fluoro-, and 2-chloro-substituted benzoic acids. With the correct substrate ratio, catalyst combination, and base, symmetrical and unsymmetrical biaryls can be readily synthesized through the Pd-catalyzed decarboxylative homo- and heterocoupling of substituted benzoic acids.
- Xie, Kai,Wang, Sizhuo,Yang, Zhiyong,Liu, Jidan,Wang, Anwei,Li, Xiujian,Tan, Ze,Guo, Can-Cheng,Deng, Wei
-
supporting information; experimental part
p. 5787 - 5790
(2011/11/06)
-
- Synthesis of polyfluoroaromatic ketones from polyfluoroarylzinc compounds and acyl chlorides in the presence of CuCl
-
Polyfluoroaromatic ketones ArFCOAlk and ArFCOPh (ArF = C6F5, 3- and 4-F3CC 6F4, 4-NCC6F4, 4-EtOCOC 6F4, C5F
- Vinogradov,Krasnov,Platonov
-
experimental part
p. 344 - 351
(2010/09/12)
-
- Copper-catalyzed decarboxylase cross-coupling of potassium polyfluorobenzoates with aryl iodides and bromides
-
Chemical Equitation Presentation For copper only: The decarboxylative cross-coupling of readily accessible and nonvolatile potassium polyfluorobenzoates with aryl iodides and bromides using a copper catalyst provides poly-fluorobiaryls and polyfluorostilb
- Shang, Rui,Fu, Yao,Wang, Yan,Xu, Qing,Yu, Hai-Zhu,Liu, Lei
-
supporting information; experimental part
p. 9350 - 9354
(2010/03/04)
-
- Coupling reactions of chlorofluoro and perfluoroalkyl iodides
-
Coupling reactions of chlorofluoro- and perfluoroalkyl iodides R f-I with Rf = ClCF2CFCl-(CF2) 3CF2-, ClCF2CFClO(CF2) 3CF2-, ClCF2CFCl-, (CF3) 2CF- , (CF3)2CFCF2CF2- in the presence of a zinc/solvent system give dimers in good yields. Both homodimerizations (one iodide) and heterodimerizations (two different iodides) have been studied. The effect of temperature and solvent is shown. The zinc mediated dechlorination of vicinal chlorine atoms in the dimers afforded terminal alkenes and dienes.
- Wlassics, Ivan,Tortelli, Vito
-
scheme or table
p. 1719 - 1728
(2009/06/05)
-
- Copper(II) acetate catalyzed cross-coupling of pentafluorophenylboronic acid with amines under an atmosphere of oxygen
-
Under an atmosphere of oxygen and a catalytic amount of Cu(OAc) 2, pentafluorophenylboronic acid reacted with anilines at room temperature to produce the corresponding N-pentafluorophenylanilines in moderate to good yields. In the case of alkylamines, unexpected N-alkyl-2,2′,3, 3′,4′,5,5′,6,6′-nona-fluorobiphenyl-4-amines were formed under the similar conditions in moderate yields. Georg Thieme Verlag Stuttgart.
- Zhong, Weihui,Liu, Zhenyu,Yu, Chuanming,Su, Weike
-
experimental part
p. 2888 - 2892
(2009/05/07)
-
- Reductive elimination of C6F5-C6F 5 in the reaction of bis(pentafluorophenyl)palladium(ii) complexes with protic acids
-
Reductive elimination of C6F5-C6F 5 from cis-[Pd(C6F5)2L] (L = cod, bpy, and dppb) was promoted by Bronsted acids. HNO3 is a convenient acid for the formation of C6F5-C 6F5 from [Pd(C6F5) 2(cod)]. The products are controlled by the auxiliary ligand.
- Koizumi, Take-Aki,Yamazaki, Atsuko,Yamamoto, Takakazu
-
body text
p. 3949 - 3952
(2009/02/03)
-
- The effect of N-heterocyclic carbene ligands in the palladium-catalyzed cross-coupling reaction of K[C6F5BF3] with aryl iodides and aryl bromides
-
The effect of N-heterocyclic carbene (NHC) ligands on the catalytic activity of in situ generated palladium complexes in the model cross-coupling reaction of K[C6F5BF3] with 4-FC6H4I was studied. Based on the obtained results, a series of pentafluorobiphenyls C6F5C6H4X were prepared from K[C6F5BF3] and XC6H4I or 4-CF3C6H4Br in high yields under aerobic conditions.
- Adonin, Nicolay Yu.,Babushkin, Dmitrii E.,Parmon, Valentin N.,Bardin, Vadim V.,Kostin, Gennadiy A.,Mashukov, Vasiliy I.,Frohn, Hermann-Josef
-
p. 5920 - 5924
(2008/09/21)
-
- From hypervalent xenon difluoride and aryliodine(III) difluorides to onium salts: Scope and limitation of acidic fluoroorganic reagents in the synthesis of fluoroorgano xenon(II) and iodine(III) onium salts
-
Fluorinated organodifluoroboranes RfBF2 are in general suitable reagents to transform XeF2 and RIF2 into the corresponding onium tetrafluoroborate salts [RfXe][BF4] and [R(Rf)I][BF4], respectively. (4-C5F4N)BF2 and trans-CF3CF{double bond, long}CFBF2 which represent boranes of high acidity form no Xe-C onium salts in reactions with XeF2 but give the desired iodonium salts with RIF2 (R = C6F5, o-, m-, p-C6FH4). The reaction of (4-C5F4N)BF2 with XeF2 ends with a XeF2-borane adduct. C6F5Xe(4-C5F4N), the first Xe-(4-C5F4N) compound, was obtained when C6F5XeF was reacted with Cd(4-C5F4N)2. We describe the synthesis of (4-C5F4N)IF2 and reactions of (4-C5F4N)IF2 and C6F5IF2 with (4-C5F4N)BF2. Analogous to [(4-C5F4N)2I][BF4] and [C6F5(4-C5F4N)I][BF4] aryl(perfluoroalkenyl)iodonium salts [R(R′)I][BF4] were obtained from RIF2 (R = C6F5, o-, m-, p-C6FH4) and R′BF2 (R′ = trans-CF3CF{double bond, long}CF, CF2{double bond, long}CF). The gas phase fluoride affinities pF- of selected fluoroorganodifluoroboranes RfBF2 and their hydrocarbon analogs are calculated (B3LYP/6-31+G*) and discussed with respect to their potential to introduce Rf-groups into hypervalent EF2 bonds. Four aspects which influence the transformation of hypervalent EF2 bonds (E = Xe, R′I) under the action of Lewis acidic reagents RAFn-1 (A = B, P; n = 3, 5) into the corresponding [RE][AFn+1] salts are presented and the important role of the acidity is emphasized. Fluoride affinities may help to plan the introduction of organo groups into EF2 moieties and to expand the types of acidic reagents. Thus C6H5PF4 with a pF- value comparable to that of RfBF2 compounds is able to introduce the C6H5 group into RIF2 (R = C6F5, p-C6FH4).
- Abo-Amer, Anwar,Frohn, Hermann-Josef,Steinberg, Christoph,Westphal, Ulrich
-
p. 1311 - 1323
(2008/12/21)
-
- Mild and general conditions for the cross-coupling of aryl halides with pentafluorobenzene and other perfluoroaromatics
-
(Chemical Equation Presented) New reaction conditions are described that enable the direct arylation of pentafluorobenzene with sterically encumbered aryl bromides and aryl chlorides. These reactions occur in high yield and under mild conditions. Notably, the reactions can be performed at 80°C in isopropyl acetate with a catalyst generated by the in situ mixing of Pd(OAc)2 and S-Phos. The enhanced scope of these transformations should further reduce the need to use pentafluorophenylboronic acid in the construction of perfluoroarenes.
- Lafrance, Marc,Shore, Daniel,Fagnou, Keith
-
p. 5097 - 5100
(2007/10/03)
-
- Pd-catalyzed desulfonylative homocoupling of arenesulfonyl chlorides in the presence of hexamethyldisilane forming biaryls
-
Arenesulfonyl chlorides undergo desulfonylative homo-coupling upon heating with hexamethyldisilane in the presence of Pd2(dibenzylideneacetone) 3?CHCl3 as a precatalyst to afford biaryls. Diaryl sulfides are occasionally formed as byproducts.
- Kashiwabara, Taigo,Tanaka, Masato
-
p. 7125 - 7128
(2007/10/03)
-
- Organometallic gold(III) compounds as catalysts for the addition of water and methanol to terminal alkynes
-
Different inorganic and organometallic gold(III) and gold(I) complexes have been tested in the addition of water and methanol to terminal alkynes. Anionic and neutral organometallic gold(III) compounds can efficiently mediate these reactions in neutral media in refluxing methanol. The compounds are added in catalytic amounts (1.6-4.5 mol% with respect to the alkyne), Thus, compounds of the general formula Q[AuRCl3], Q[AuR2Cl2], [AuRCl2]2, and [AuR2Cl]2, (Q = BzPPh3+, PPN: N(PPh3)2+ or N(Bu)4+; R = C6F5 or 2,4,6-(CH3)3C6H2) seem to behave as Lewis acids in nucleophilic additions to triple bonds. Some intermediates could be detected in the stoichiometric reaction between [Au(C6F 5)2Cl]2 and phenylacetylene that was followed by variable temperature 1H, 19F{1H}, COSY 19F{1H}-19F{1H}, and 2H{1H} NMR experiments. Compound [Au(C6F 5)2Cl]2 is also able to catalyze the hydration of phenylacetylene at room temperature. A plausible mechanism for the hydration reaction has been proposed.
- Casado, Raquel,Contel, Maria,Laguna, Mariano,Romero, Pilar,Sanz, Sergio
-
p. 11925 - 11935
(2007/10/03)
-
- Promotion of reductive elimination reaction of diorgano(2,2′-bipyridyl)nickel(II) complexes by electron-accepting aromatic compounds, Lewis acids, and Bronsted acids
-
Reductive elimination of R-R from dialkyl(2,2′-bipyridyl)nickel(II), [NiR2(bpy)] 1 (R = CH3 (1a), C2H5 (1b), n- C3H7 (1c)), caused by π-coordination of electron-accepting aromatic compounds and reductive elimination of Ar-Ar from [NiAr2(bpy)] 2 (Ar = C6F5 (2a) and pyrazolyls (2b and 2c)) promoted by electron-accepting aromatic compounds, Lewis acids, and Bronsted acids have been investigated. 1H-NMR and kinetic data indicate that π-coordination of the electron-accepting aromatic compound to [NiR2(bpy)] leads to the reductive elimination of R-R. The rate of the reductive elimination obeys the second-order rate law, -d[1]/dt = k[1][electron-accepting aromatic compound]. Plots of log k vs Σσp of the electron-accepting aromatic compound give a line with a slope of 1.8. Bronsted acids cause reductive elimination of Ar-Ar from 2 selectively under several reaction conditions (e.g., 2a with CF3COOH in air and 2b with HBr). The reductive elimination reaction of 2a caused by CF3COOH obeys the second-order rate law, -d[2a]/dt = k′[2a][CF3COOH], in air. The reaction of 2b with H2SO4 requires O2, giving the rate equation, -d[2b]/dt = k″[2b]2[O2]; k″ increases with [H2SO4], reaching a maximum value at a high [H2SO4]. UV-vis spectroscopy reveals the presence of the following equilibrium: 2b + H2SO4 ? 2b·H2SO4, and the equilibrium constant Ka is evaluated as Ka = [2b·H2SO4]/ ([2b][H2SO4]) = 47 M-1 at 300.5 K. UV-vis data give information about the electronic states of 2 and the 2b-Bronsted acid adduct. Poly(6-hexylpyridine-2,5-diyl) with a higher molecular weight has been prepared according to the basic information.
- Yamamoto, Takakazu,Abla, Mahmut,Murakami, Yasuharu
-
p. 1997 - 2009
(2007/10/03)
-
- Synthesis and Properties of 1,1,3,3-Tetrakis(pentafluorophenyl)-cyclo-di(silthiane) and Related Compounds
-
The synthesis of tetrakis(pentafluorophenyl-cyclo-di(silthiane) and related compounds by reacting organosubstituted silanes with sulfur or hexamethyldisilthiane is reported.The compounds are characterized by analysis, by relative molecular mass, by 1H, 13C, 19F, and 29Si NMR spectroscopy, and by mass and IR spectra, respectively.Two 29Si NMR signals of different intensity found for compounds with two different organic substituents on silicon are explained by the existence of diastereomers. - Keywords: Perfluoro-organic cyclo-di(silthianes); Synthesis; NMR spectra; Diastereomers
- Horn, H.-G.,Probst, M.
-
p. 1169 - 1178
(2007/10/03)
-
- Perfluororganochalkogeno-ketene. III. Bis(pentafluorphenylsulfanyl)keten (C6F5S)2C=C=O; Synthesen und Charakterisierung
-
Bis(pentafluorophenylsulfanyl)ketene (1) may be prepared in good yield by the dehydration of the corresponding substituted acetic acid (C6F5S)2CHC(O)OH (4b) with P4O10 or by the reaction of C6F5SCl with Ag2CCO.The starting material 4b is prepared from CH3C(OCH2CH3)3 and C6F5SCl.Acidolysis of the C6F5S-substituted orthoesters 2 provided the ethyl esters CH3-n(SC6F5)nC(O)OCH2CH3 (3) and acetic acids CH3-n(SC6F5)nC(O)OH (4).
- Haas, Alois,Praas, Hans-Walter,Radau, Godehard
-
p. 257 - 260
(2007/10/02)
-
- Reactions of pentafluorophenylxenon(II) hexafluoroarsenate (+)(-) with aromatic compounds
-
Pentafluorophenylxenon(II) hexafluoroarsenate (+)(-) reacts (MeCN, 20 deg C) with aromatic compounds C6H5X (X=CH3, F, CF3, NO2 and CN), yielding isomeric mixtures of polyfluorinated biphenyls XC6H4C6F5.When X=I, iodopentafluorobenzene is formed in addition, whereas trimethylsilylbenzene (X=SiMe3) is only converted to C6H5C6F5 and C6F5H.These results are compared with the data for the radical pentafluorophenylation and fluorination reactions of the corresponding aromatic compounds with XeF2.Polyfluoroaromatic compounds C6F6, C6F5H, C6F5I, C6F5CN and C6F5SiMe3 do not react with (+)(-) under the same conditions.
- Frohn, H. J.,Klose, A.,Bardin, V. V.
-
p. 201 - 216
(2007/10/02)
-
- Synthesis and properties of partially fluorinated 4-alkyl-4′-cyanobiphenyls - Part II 4-alkyl-4′-cyano-2′3′5′6′-tetrafluorobiphenyls
-
A general synthetic route to 4-alkyl-4′-cyano-2′3′5′6′-tetrafluorobiphenyls has been developed and used to prepare compounds with unbranched alkyl chains ranging from 4 to 7 carbon atoms. The compounds were characterised by 19F 13C and 1H NMR spectroscopy. One member of the series 4-butyl-4′-cyano-2′3′3′5′6′- tetrafluorobiphenyl was characterised crystallographically at 147 K.
- Field, Leslie D.,Hambley, Trevor W.,Pierens, Gregory K.
-
p. 7069 - 7080
(2007/10/02)
-
- The Pentafluorophenylxenon(II) Cation: +; The First Stable System with a Xenon-Carbon Bond
-
Pentafluorophenylxenon(II) pentafluorophenyltrifluoroborate, +-, can be prepared analogously to pentafluorophenylhalogen(III) and (V) fluorides, C6F5HalF2 and C6F5HalF4 (with Hal=Br or I), by nucleophilic displacement of fluorine in XeF2 using B(C6F5)3 as an aryl-transfer reagent; the resulting colourless solid with a stable xenon-carbon bond is characterised in solution by (129)Xe and (19)F n.m.r. and chemically as an electrophilic transfer reagent for pentafluorophenyl groups.
- Frohn, Hermann J.,Jakobs, Stephanus
-
p. 625 - 627
(2007/10/02)
-
- Direct Formation of Organocopper Compounds by Oxidative Addition of Zerovalent Copper to Organic Halides
-
Mixing a solution of CuI*P(Et)3 with a stoichiometric amount of lithium naphthalide in THF affords a zerovalent copper species that is sufficiently reactive to add to organic halides to give the corresponding organocopper compounds.
- Ebert, Greg W.,Rieke, Reuben D.
-
p. 5280 - 5282
(2007/10/02)
-
- REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA IV.* THE NUCLEOPHILIC AND PROTOPHILIC ACTIVITY OF METHOXIDE AND HYDROXIDE IONS IN REACTIONS WITH POLYFLUORINATED AROMATIC COMPOUNDS
-
In the reaction of polyfluorinated derivatives of benzene with potassium methoxide in liquid ammonia a fluorine atom is substituted by a methoxy group.With potassium hydroxide reactions involving removal of a proton from a ring carbon atom take place preferentially.The possibility of polyfluoroarylation and methylation catalyzed by potassium hydroxide in polyfluorinated aromatic compounds, based on capture of the polyflurinated aryl anion by the electrophile, was demonstrated.
- Shtark, A. A.,Chuikova, T. V.,Shteingarts, V. D.
-
p. 960 - 967
(2007/10/02)
-
- Complexes of (C6F5)2Co and (C6F5)2Ni. Synthesis of (η6-arene)bis(pentafluorophenyl)cobalt(II) using cobalt atoms. Reactions, η6-arene lability, and use in synthesis of tetrahedral (C6F5)2Co(L)2
-
The high lability of the η6-arene ligand in (C6F6)2Co(η6-arene) has been used to advantage to prepare new (C6F5)2Co(L)2 and (C6F5)2Co(L-L) complexes (L = tetrahydrofuran, tetrahydrothiophene, and pyridine and L-L = bipyridine). According to spectral and magnetic data these are tetrahedral compounds. Similar π-arene displacements on (C6F5)2Ni(η6-arene) have yielded square-planar trans-(C6F5)2Ni(L)2 and square-planar cis-(C6F6)2Ni(L-L). The starting cobalt-arene complex induced the polymerization of norbornadiene and propyne. Thermolysis of the starting complex led to free radical decomposition, which is contrasted by nonradical reductive coupling with the nickel analogue. η6-Arene-exchange equilibria for the cobalt- and nickel-arene complexes indicated the order of preference for η6-arenes as mesitylene > toluene > benzene > anisole for cobalt and mesitylene > toluene ≈ anisole > benzene for nickel. A literature background regarding monoarene complexes is presented.
- Brezinski, Michael M.,Klabunde, Kenneth J.
-
p. 1116 - 1123
(2008/10/08)
-
- Activated Metallic Nickel as a Reagent for the Dehalogenative Coupling of Halobenzenes
-
Activated metallic nickel powder, prepared by the reduction of nickel halides with lithium and with naphthalene as an electron carrier, is a simple and convenient reagent for the dehalogenative coupling of iodobenzenes and bromobenzenes under mild conditions.The intermediates, ArNiX and Ar2Ni species (Ar=C6F5), were isolated as the phosphine complexes.
- Matsumoto, Hideyuki,Inaba, Shin-ichi,Rieke, Reuben D.
-
p. 840 - 843
(2007/10/02)
-
- METALLIC NICKEL AS A REAGENT FOR THE COUPLING OF AROMATIC BENZYLIC HALIDES
-
The oxidative addition of aromatic and benzylic halides to activated metallic nickel occured under mild conditions to give the corresponding dehalogenative coupled products in good yields.
- Inaba, Shin-ichi,Matsumoto, Hideyuki,Rieke, Reuben D.
-
p. 4215 - 4216
(2007/10/02)
-