13029-08-8Relevant articles and documents
Pd(OAc)2 catalyzed homocoupling of arenediazonium salts in ionic liquids: Synthesis of symmetrical biaryls
Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
, p. 663 - 667 (2016)
A facile, high yielding, and simple method for the synthesis of a library of symmetrical biaryls by homocoupling of arenediazonium salts is reported, employing catalytic amounts of Pd(OAc)2 and the readily available imidazolium ionic liquids (ILs), without oxidants, ligands, additives, or volatile solvents. Simple product isolation and recycling/reuse of the IL represent additional advantages of this method.
Palladium-catalyzed reductive homocoupling of aryl sulfonates via cleavage of C─O bond at room temperature
Zhong, Shuangling,Chen, Mengxin,Liu, Ge,Sun, Chenggang,Liu, Wencong
, (2017)
Palladium-catalyzed reductive homocoupling of aryl sulfonates has been successfully achieved under mild conditions. This transformation is a new method for the homocoupling reaction of aryl sulfonates at room temperature via the cleavage of C─O bonds, thus providing an alternative synthesis of symmetric biaryls. The reported reductive homocoupling reaction is tolerant of many common functional groups regardless of electron-donating or electron-withdrawing nature, making this newly developed transformation important for complementing Ullmann coupling. Experimental Section. Typical procedure for the products.
Glucopyranoside-substituted imidazolium-based chiral ionic liquids for Pd-catalyzed homo-coupling of arylboronic acids in water
Huang, Zhiqiang,Kong, Lingfang,Li, Jing,Wu, Yue,Xue, Jun,Yuan, Yangyang,Zhou, Zhonggao
, p. 1 - 12 (2020)
Chiral ionic liquids (CILs) are widely used solvents and materials with prominent properties. Carbohydrate-derived imidazolium-based CILs represent a distinctive type of CILs possessing multiple chiral centers from natural chiral pool. Herein, a series of glucopyranoside-substituted imidazolium-based CILs (Glu-imi-CILs) were synthesized and evaluated as ligands for Pd-catalyzed homo-coupling reactions of arylboronic acids in water. The glucopyranoside substituent was instrumental for improving the catalytic activity of the resulting catalysts. Moreover, a Glu-imi-CIL with a free hydroxyl group for additional coordination was found to be the most efficient ligand. A series of symmetric biaryl compounds (13 examples) were synthesized from arylboronic acids by this method in high isolated yields (85?99percent).
Exploring the coordination confinement effect of divalent palladium/zero palladium doped polyaniline-networking: As an excellent-performance nanocomposite catalyst for C-C coupling reactions
Liang, Yanping,Liu, Wanyi,Song, Manrong,Sun, Yanyan,Wang, Gang,Wu, Zhiqiang,Zhan, Haijuan
, p. 177 - 188 (2020)
A pre-formed catalyst Pd2+/PANI composite for C-C coupling reaction was synthesized by combining the self-stabilized dispersion polymerization method with the in-situ composite material. Experiments have confirmed that the relatively high reduced structure (75%) in the polyaniline carrier is more favorable for the coupling reaction. Raman spectroscopy, solid nuclear magnetic, and X-ray photoelectron spectroscopy were performed to characterize the structures. The pre-formed catalyst has uniform coordination of divalent palladium and nitrogen in different valence states of the carrier polyaniline, which shows a good synergistic effect in the catalytic Ullmann reaction, and greatly reduces the use of reducing agents such as hydrazine hydrate. Compared with other studies, we analyzed the catalytic reaction mechanism in detail through real-time online infrared and XPS characterization. The results show that the divalent palladium in the catalyst and the zero-valent palladium generated by the in-situ reaction synergistically promote the reaction, while the polyaniline support acts as a stabilizer and dispersant, which prevents the agglomeration of the metal particles and prolongs increased catalyst life. The prepared Pd2+/PANI composites will become the most attractive alternative to traditional organic materials due to their wide applicability, high catalytic activity, stable recycling and relatively low price. This work provides a new theoretical basis for the understanding of the essential driving force of PANI catalytic activity and the cognition of the micro mechanism of action.
Efficient Pd-catalyzed oxidative homocoupling of arylboronic acids in aqueous NaClO
Li, Min-Xin,Tang, Yan-Ling,Gao, Hui,Mao, Ze-Wei
, (2020)
An efficient, mild and practical method was developed for the synthesis of biaryls via the Pd-catalyzed oxidative homocoupling of aromatic/heteroaromatic boronic acids in aqueous NaClO.
Influence of chlorine substituent positions on the molecular structure and the torsional potentials of dichlorinated biphenyls: R2PI spectra of the first singlet transition and AM1 calculations
Zimmermann, R.,Weickhardt, C.,Boesl, U.,Schlag, E. W.
, p. 81 - 98 (1994)
Resonance enhanced two-photon ionization (R2PI) spectra of biphenyl and four dichlorinated biphenyl derivatives (2,6-, 2,2'-, 4,4'- and 2,4'-dichlorobiphenyl) cooled in a supersonic jet expansion have been measured in the region of the S1 0 transition (34500-36900 cm-1).The biphenyl derivatives show different torsional angles between the two phenyl rings.The degree of torsion depends on the positions of the substituents due to differing steric and electronic effects on the biaryl chromophore.Furthermore the dihedral angle changes upon electronic excitation.Therefore the electronic spectra of all investigated compounds show a vibronic substructure, dominated by Franck-Condon induced progressions of the torsional mode.Nevertheless the four dichlorobiphenyl spectra differ both in energetic locations and vibronic structure.The molecular structures and torsional potentials have been studied by molecular orbital calculations using the AM1 method.The complex structure of the R2PI spectra has been interpreted with the help of these calculations.In addition, the use of R2PI as an analytical tool is demonstrated.R2PI of jet-cooled aromatic molecules provides the possibility of species and isomer selective ionization from a complex mixture.In the case of polychlorinated biphenyls (PCBs) an isomer selective registration of the important toxic (coplanar) PCBs should be possible.
New N,N'-bis(substituted phenylazo)piperazines and their cleavage reactions in acetic acid
Yanarates, Erkan,Disli, Ali,Yildirir, Yilmaz
, p. 429 - 433 (1999)
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A site-selective and stereospecific cascade Suzuki-Miyaura annulation of alkyl 1,2-bisboronic esters and 2,2′-dihalo 1,1′-biaryls
Willems, Suzanne,Toupalas, Georgios,Reisenbauer, Julia C.,Morandi, Bill
supporting information, p. 3909 - 3912 (2021/04/26)
A cascade Suzuki-Miyaura cross-coupling giving rise to 9,10-dihydrophenanthrenes has been developed. Using biaryls with unsymmetrical substitution-pattern full site-selectivity was observed. Furthermore, this cross-coupling of an alkyl 1,2-bisboronic pinacol ester proceeds through the challenging coupling of a secondary boronate with complete stereoretention.
