69168-29-2Relevant academic research and scientific papers
C(acyl)-C(sp2) and C(sp2)-C(sp2) Suzuki-Miyaura cross-coupling reactions using nitrile-functionalized NHC palladium complexes
?akir, Sinem,Karabiyik, Hande,Kavukcu, Serdar Batikan,Rethinam, Senthil,Türkmen, Hayati
, p. 37684 - 37699 (2021/12/09)
Application of N-heterocyclic carbene (NHC) palladium complexes has been successful for the modulation of C-C coupling reactions. For this purpose, a series of azolium salts (1a-f) including benzothiazolium, benzimidazolium, and imidazolium, bearing a CN-substituted benzyl moiety, and their (NHC)2PdBr2 (2a-c) and PEPPSI-type palladium (3b-f) complexes have been systematically prepared to catalyse acylative Suzuki-Miyaura coupling reaction of acyl chlorides with arylboronic acids to form benzophenone derivatives in the presence of potassium carbonate as a base and to catalyse the traditional Suzuki-Miyaura coupling reaction of bromobenzene with arylboronic acids to form biaryls. All the synthesized compounds were fully characterized by Fourier Transform Infrared (FTIR), and 1H and 13C NMR spectroscopies. X-ray diffraction studies on single crystals of 3c, 3e and 3f prove the square planar geometry. Scanning Electron Microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), metal mapping analyses and thermal gravimetric analysis (TGA) were performed to get further insights into the mechanism of the Suzuki-Miyaura cross coupling reactions. Mechanistic studies have revealed that the stability and coordination of the complexes by the CN group are achieved by the removal of pyridine from the complex in catalytic cycles. The presence of the CN group in the (NHC)Pd complexes significantly increased the catalytic activities for both reactions.
Ag/Pd Cocatalyzed Direct Arylation of Fluoroarene Derivatives with Aryl Bromides
Panigrahi, Adyasha,Whitaker, Daniel,Vitorica-Yrezabal, I?igo J.,Larrosa, Igor
, p. 2100 - 2107 (2020/02/28)
Diverse C-H functionalizations catalyzed by Pd employ Ag(I) salts added as halide abstractors or oxidants. Recent reports have shown that Ag can also perform the crucial C-H activation step in several of these functionalizations. However, all of these processes are limited by the wasteful requirement for (super)stoichiometric Ag(I) salts. Herein, we report the development of a Ag/Pd cocatalyzed direct arylation of (fluoroarene) chromium tricarbonyl complexes with bromoarenes. The small organic salt, NMe4OC(CF3)3, added as a halide abstractor, enables the use of a catalytic amount of Ag, reversing the rapid precipitation of AgBr. We have shown through H/D scrambling and kinetic studies that a (PR3)Ag-alkoxide is responsible for C-H activation, a departure from previous studies with Ag carboxylates. Furthermore, the construction of biaryls directly from the simple arene is achieved via a one-pot chromium tricarbonyl complexation/C-H arylation/decomplexation sequence using (pyrene)Cr(CO)3 as a Cr(CO)3 donor.
Continuous-Flow Synthesis of Biaryls by Negishi Cross-Coupling of Fluoro- and Trifluoromethyl-Substituted (Hetero)arenes
Roesner, Stefan,Buchwald, Stephen L.
supporting information, p. 10463 - 10467 (2016/08/24)
A continuous-flow method for the regioselective arylation of fluoroarenes and fluoropyridines has been developed. The telescoped procedure reported here consists of a three-step metalation, zincation, and Negishi cross-coupling sequence, providing efficient access to a variety of functionalized 2-fluorobiaryl products. Precise temperature control of the metalation step, made possible by continuous-flow technology, allowed for the efficient preparation of the arylated products in high yields and short residence times. Additionally, several examples of the regioselective arylation of benzotrifluoride derivatives are also provided.
The superbase approach to flurbiprofen: An exercise in optionally site-selective metalation
Schlosser, Manfred,Geneste, Herve
, p. 1969 - 1973 (2007/10/03)
A superior route to the analgesic flurbiprofen has been devised. Key steps are the selective deprotonation of 3-fluorotoluene with tert-butyllithium in the presence of potassium tert-butoxide (LIT-KOR) at the 4-position and the selective deprotonation of the 4-methyl-2-fluorobiphenyl with lithium diisopropylamide in the presence of potassium tert-butoxide (LIDA-KOR) at the benzylic position. Depending on the reagent and the substituent pattern, the 3- and 5-positions of 2-fluorobiphenyls can also be specifically attacked.
Method for the preparation of 2-fluoro-4-monobromomethylbiphenyl
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, (2008/06/13)
2-(2-Fluoro-4-biphenylyl)propionic acid is prepared from 2-amino-4-methyl-biphenyl via a series of novel intermediates. In particular 2-amino-4-methylbiphenyl is converted to 2-fluoro-4-methylbiphenyl, the methyl group is brominated to form 2-fluoro-4-monobromomethylbiphenyl which is transformed into 2-(2-fluoro-4-biphenylyl)acetonitrile. This acetonitrile is then converted to fluorbiprofen via the corresponding propionitrile or it may be converted into fluorbiprofen via the intermediate ethyl-2-(2-fluoro-4-biphenylyl)-2-cyanopropionate.
