27521-80-8Relevant articles and documents
Synthesis and reactivity of metal carbene complexes with heterobiaryl spacer substituents
Lotz, Simon,Crause, Chantelle,Olivier, Andrew J.,Liles, David C.,Goerls, Helmar,Landman, Marile,Bezuidenhout, Daniela I.
, p. 697 - 710 (2009)
Mono- and binuclear Fischer carbene complexes, [M(CO)5{C(OR)Ar- ArX}], X = H, {C(OR)M′(CO)5}; M, M′ = W or Cr; R = Me, Et or (CH2)4OMe; Ar = thiophene, N-methylpyrrole or furan units 1-20, were synthesized. For
Synthesis and structural, electronic, and optical properties of oligo(thienylfuran)s in comparison with oligothiophenes and oligofurans
Miyata, Yasuo,Nishinaga, Tohru,Komatsu, Koichi
, p. 1147 - 1153 (2005)
(Chemical Equation Presented) Alternate thiophene/furan oligomers having four and six heterocycles, i.e., oligo(thienylfuran) dimer and trimer 2 (n = 4 and 6), were newly synthesized by repetitive Stille coupling reactions. The structural, electronic, and optical properties of these oligomers were investigated by X-ray crystallography (for n = 4), cyclic voltammetry (CV), UV-vis and fluorescence spectroscopy, and DFT calculations, and the results were compared with those of corresponding oligothiophenes (1) and oligofurans (3). The inter-ring torsional energy profiles calculated for bithiophene 1 (n = 2), thienylfuran 2 (n = 2), and bifuran 3 (n = 2) at the B3LYP/6-31G(d) level indicated that the most stable conformers of 2 (n = 2) and 3 (n = 2) are fully coplanar with transoid structure while that of 1 (n = 2) is twisted with a dihedral angle of 158°. In accord with this, X-ray crystallographic analysis of 2 (n = 4) revealed that the π-conjugated system is nearly planar with the inter-ring C=C-C=C dihedral angles between the thiophene and furan rings of 173.6(7)°, -177.0(7)°, and 172.6(6)°. In the packing structure, these nearly planar molecules are arranged in a herringbone pattern. The CV on a series of oligo(thienylfuran)s 2 showed irreversible oxidation peaks at +0.90, +0.42, and +0.29 V vs Fc/Fc+ for n = 2, 4, and 6, which were 0.15-0.18 V lower than those for corresponding oligothiophenes 1 and were closer to those for oligofurans 3. On the other hand, the UV-vis spectra of 2 showed the longest wavelength absorption to be almost identical with those of the corresponding 1, and more bathochromically shifted than those of the corresponding 3. The results of CV and UV-vis measurements were supported by DFT calculations (B3LYP/ 6-311+G(2d,p)//B3LYP/6-31G(d)). Thus, oligo(thienylfuran)s 2 have HOMOs which are higher than those of oligothiophenes 1 and close to those of 3, and HOMO-LUMO gaps which are close to those of 1 and smaller than those of 3. In fluorescence spectra, the quantum yield of 2 increased with elongation of the π-system (n = 2 (3.5%), 4 (19%), 6 (24%)).
Cycloisomerization of Conjugated Allenones into Furans under Mild Conditions Catalyzed by Ligandless Au Nanoparticles
Zorba, Leandros,Kidonakis, Marios,Saridakis, Iakovos,Stratakis, Manolis
, p. 5552 - 5555 (2019/08/01)
Au nanoparticles supported on TiO2 (1 mol %) catalyze the quantitative cycloisomerization of conjugated allenones into furans under very mild conditions. The reaction rate is accelerated by adding acetic acid (1 equiv), but the acid does not participate in the protodeauration step as in the corresponding Au(III)-catalyzed transformation. The process is purely heterogeneous, allowing thus the recycling and reuse of the catalyst effectively in several runs.
N-Heterocarbene Palladium Complexes with Dianisole Backbones: Synthesis, Structure, and Catalysis
Li, Dong-Hui,He, Xu-Xian,Xu, Chang,Huang, Fei-Dong,Liu, Ning,Shen, Dong-Sheng,Liu, Feng-Shou
, p. 2539 - 2552 (2019/06/17)
A series of palladium N-heterocyclic carbenes (NHCs), complexes C1-C5, bearing dianisole backbones and substituted N-aryl moieties have been synthesized and characterized. The electronic effect as well as the steric environment of the NHC ligands has been assessed. The synthesized palladium complexes were applied for Suzuki-Miyaura cross-coupling reactions under aerobic conditions. The relationship between the catalytic structure and catalytic performance was then extensively investigated. Upon optimizing the reaction conditions, the C4 was found to be highly efficient to catalyze the cross-coupling of (hetero)aryl chlorides with (hetero)arylboronic acids at a 0.1 mol % palladium loading.
Synthesis of 2,5-Disubstituted Furans from Sc(OTf)3 Catalyzed Reaction of Aryl Oxiranediesters with γ-Hydroxyenones
Mondal, Keshab,Pan, Subhas Chandra
, p. 4415 - 4421 (2017/04/27)
A convenient synthesis of 2,5-disubstituted furan was developed by employing donor-acceptor oxiranes in a new reaction with γ-hydroxyenones. Sc(OTf)3 was found to be the best catalyst, and 2,5-disubstituted furans are obtained in moderate to good yields under mild reaction conditions. The scope of the reaction is quite decent, allowing for the synthesis of disubstituted furans having aryl and heteroaromatic groups.
Palladacycle-catalyzed Suzuki-Miyaura reaction of aryl/heteroaryl halides with MIDA boronates in EtOH/H2O or H2O
Li, Yabo,Wang, Jingran,Wang, Zhiwei,Huang, Mengmeng,Yan, Beiqi,Cui, Xiuling,Wu, Yusheng,Wu, Yangjie
, p. 36262 - 36266 (2014/11/08)
With good to excellent yields, a series of mono- or diheteroaryl compounds were synthesized via the palladacycle-catalyzed Suzuki-Miyaura reaction of various N-methyliminodiacetic acid (MIDA) boronates with aryl/heteroaryl halides in EtOH/H2O or H2O. This journal is the Partner Organisations 2014.
General suzuki coupling of heteroaryl bromides by using tri-tert-butylphosphine as a supporting ligand
Zou, Yinjun,Yue, Guizhou,Xu, Jianwei,Zhou, Jianrong
supporting information, p. 5901 - 5905 (2015/03/30)
A general procedure for the fast Suzuki coupling of major families of heteroaryl bromides was realized by using Pd(OAc)2/PtBu3 as the catalyst. Many couplings were finished within minutes at room temperature in n-butanol. Different from previous studies, three typical heteroaryl bromides were systematically examined in couplings of various heteroaryl and aryl boronic acids. A fast, general coupling of heteroaryl bromides is realized by using a single palladium catalyst supported by tri-tert-butylphosphine.
Room-temperature Suzuki-Miyaura coupling of heteroaryl chlorides and tosylates
Yang, Junfeng,Liu, Sijia,Zheng, Jian-Feng,Zhou, Jianrong
supporting information, p. 6248 - 6259,12 (2020/09/16)
Suzuki-Miyaura coupling of heteroaryls is an important method for the preparation of compound libraries for medicinal chemistry and materials research. Although many catalysts have been developed, none of them have been generally applicable to the coupling reactions of heteroaryl chlorides and tosylates at room temperature. We discovered that a catalyst combination of Pd(OAc)2 and XPhos (2-dicyclohexylphosphanyl-2',4',6'- triisopropylbiphenyl) could efficiently catalyze these couplings. Besides the choice of catalyst, the use of hydroxide bases in an aqueous alcoholic solvent was essential for fast couplings. These conditions promoted fast release of active catalyst (XPhos)Pd0, and accelerated the transmetalation in the catalytic cycle. Most of the major families of heteroaryl chlorides (31 examples) and tosylates (17 examples) reached full conversion within minutes to hours at room temperature. The method could be easily scaled up for gram-scale synthesis. Furthermore, we examined the relative reactivity of coupling partners in whole reactions. Electron-rich heteroaryl chlorides and tosylates reacted more slowly than electron-deficient ones, in the order of indole, pyrrole furan, thiophene > pyridine. Similarly, electron-deficient arylboronic acids were less reactive than electron-neutral and electron-rich ones. The reactivity trends from this study can help to choose appropriate coupling partners for Suzuki reactions.
Palladium-catalyzed reactions of enol ethers: Access to enals, furans, and dihydrofurans
Lauer, Matthew G.,Henderson, William H.,Awad, Amneh,Stambuli, James P.
, p. 6000 - 6003 (2013/02/25)
The palladium-catalyzed oxidation of alkyl enol ethers to enals, which employs low loadings of a palladium catalyst, is described. The mild oxidation conditions tolerate a diverse array of functional groups, while allowing the formation of di-, tri-, and tetrasubtituted olefins. The application of this methodology to intramolecular reactions of alkyl enol ethers containing pendant alcohols provides furan and 2,5-dihydrofuran products.
Synthesis of 2-aryl- and 2,5-diarylfurans and thiophenes by Suzuki-Miyaura reactions using potassium trifluoroborate salts and heteroaryltellurides
Botteselle, Giancarlo V.,Hough, Thomas L. S.,Venturoso, Raphael C.,Cella, Rodrigo,Vieira, Adriano S.,Stefani, Helio A.
experimental part, p. 870 - 873 (2009/04/11)
The Suzuki-Miyaura cross-coupling reaction of 2-(butyltellanyl) or 2,5-bis-(butyltellanyl)furans and thiophenes with potassium aryltrifluoroborate salts catalyzed by palladium afforded 2-aryl- or 2,5-diaryl-furans and thiophenes in moderate to good yields.
