198981-85-0Relevant academic research and scientific papers
σ-Bond initiated generation of aryl radicals from aryl diazonium salts
Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
, p. 1812 - 1819 (2020/03/17)
σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
Perylenequinonoid-catalyzed photoredox activation for the direct arylation of (het)arenes with sunlight
Zhang, Shiwei,Tang, Zhaocheng,Bao, Wenhao,Li, Jia,Guo, Baodang,Huang, Shuping,Zhang, Yan,Rao, Yijian
supporting information, p. 4364 - 4369 (2019/05/10)
Naturally occurring perylenequinonoid pigments (PQPs) have attracted considerable attention owing to their excellent properties of photosensitization. They have been widely investigated as an aspect of photophysics and photobiology. However, their applications in photocatalysis are yet to be explored. We report here that sunlight along with 1 mol% cercosporin, which is one of the perylenequinonoid pigments, catalyzes the direct C-H bond arylation of (het)arenes by a photoredox process with good regioselectivity and broad functional group compatibility. Furthermore, a gram-scale reaction with great conversions of substrates was achieved even by a cercosporin-containing supernatant without organic solvent extraction and purification after liquid fermentation. Thus we set up a bridge between microbial fermentation and organic photocatalysis for chemical reactions in a sustainable, environmentally friendly manner.
Electrolytic cross-Coupling of arenediazonium salts and heteroarenes
Hata, Dai,Tobisu, Mamoru,Amaya, Toru
supporting information, p. 1749 - 1751 (2018/11/27)
The cathodic reduction-induced cross-coupling of arenediazonium salts and heteroarenes was employed to prepare heterobiaryl derivatives. This reaction is attractive because it allows the direct arylation of an aromatic C-H bond in a heteroarene derivative. A radical chain mechanism appears to be involved.
Isomer-Specific Hydrogen Bonding as a Design Principle for Bidirectionally Quantitative and Redshifted Hemithioindigo Photoswitches
Zweig, Joshua E.,Newhouse, Timothy R.
supporting information, p. 10956 - 10959 (2017/08/21)
A new class of bidirectionally quantitative photoswitches based on the hemithioindigo (HTI) scaffold is reported. Incorporation of a pyrrole hydrogen-bond donor leads to a bathochromic shift allowing for quantitative bidirectional isomerization. Additionally, extending conjugation from the electron-rich pyrrole results in quantitative visible-light photoswitches, as well as photoswitches that isomerize with red and near-infrared light. The presence of the hydrogen bond leading to the observed redshift is supported by computational and spectroscopic evidence.
Original design of fluorescent ligands by fusing BODIPY and melatonin neurohormone
Thireau, Jeremy,Marteaux, Justine,Delagrange, Philippe,Lefoulon, Francois,Dufourny, Laurence,Guillaumet, Gerald,Suzenet, Franck
supporting information, p. 158 - 161 (2014/03/21)
An original design and synthesis of fluorescent ligands for melatonin receptor studies is presented and consists in the fusion of the endogenous ligand with the fluorescent BODIPY core. Probes I-IV show high affinities for MT1 and MT2 melatonin receptors and exhibit fluorescence properties compatible with cell observation.
One-pot synthesis of diazine-bridged bisindoles and concise synthesis of the marine alkaloid hyrtinadine A
Tasch, Boris O. A.,Merkul, Eugen,Mueller, Thomas J. J.
supporting information; experimental part, p. 4532 - 4535 (2011/10/03)
Diazine-bridged bisindoles are readily obtained from N-Bocprotected 3-iodoindoles and 3-iodo-7-azaindole in a pseudo three-component reaction involving a one-pot Masuda borylation-Suzuki arylation sequence. Some of the title com-pounds display promising c
Pd- and Ni-catalyzed cross-coupling reactions of functionalized organozinc reagents with unsaturated thioethers
Melzig, Laurin,Metzger, Albrecht,Knochel, Paul
supporting information; experimental part, p. 2948 - 2956 (2011/04/16)
A variety of unsaturated thioethers have been subjected to cross-coupling reactions with functionalized zinc reagents in the presence of a transition-metal catalyst. Three different catalytic systems based on Pd(OAc)2 or [Ni(acac)2] and the ligands S-Phos or DPE-Phos gave the best results. N-Heterocyclic thioethers based on a pyridine, pyrimidine, pyrazine, pyridazine, triazine, benzothiazole, benzoxazole, pyrrole, or quinazoline ring, as well as thiomethylacetylenes, serve as electrophiles in this cross-coupling reaction. Aryl-, heteroaryl-, benzylic, and alkylzinc halides with sensitive functionalities, such as ester, nitrile, or ketone groups react at ambient temperature with unsaturated thioethers using a Ni catalyst. The corresponding Pd-catalyzed reactions require slightly higher temperatures. Large-scale cross-coupling experiments (10-20 mmol) with N-heterocycles are also reported.
Alkoxy-substituted derivatives of π-conjugated acyclic anion receptors: Effects of substituted positions
Maeda, Hiromitsu,Eifuku, Nazuki
supporting information; experimental part, p. 208 - 209 (2010/03/01)
The synthesis, solid-state assemblies, and anion binding affinities of π-conjugated acyclic anion receptors with alkoxyphenyl substituents are discussed. The position of the alkoxy moiety is essential to determining not only the electronic state but also the anion binding affinity. Copyright
A preparatively convenient ligand-free catalytic PEG 2000 suzuki-miyaura coupling
Razler, Thomas M.,Hsiao, Yi,Qian, Feng,Fu, Ruiling,Khan, Rana Kashif,Doubleday, Wendel
supporting information; experimental part, p. 1381 - 1384 (2009/06/28)
A ligand-free Suzuki-Miyaura reaction for the cross-coupling of aryl and heteroaryl bromides with aryl and heteroarylboronic acids has been developed utilizing catalytic polyethylene glycol 2000 (PEG 2000). This preparatively convenient system afforded the corresponding cross-coupled products in good to excellent isolated yields after a simple aqueous workup. Transmission electron microscopy (TEM) analysis of the Pd-PEG 2000 catalyst system revealed in situ-generated palladium nanoparticles after only 1 min of reaction.
Palladium-catalyzed cross-coupling of five-membered heterocyclic silanolates
Denmark, Scott E.,Baird, John D.,Regens, Christopher S.
, p. 1440 - 1455 (2008/04/12)
(Chemical Equation Presented) The preparation of π-rich 2-aryl heterocycles by palladium-catalyzed cross-coupling of sodium heteroarylsilanolates with aryl iodides, bromides, and chlorides is described. The cross-coupling process was developed through extensive optimization of the following key variables: (1) identification of stable, isolable alkali metal silanolates, (2) identification of conditions for preformation and isolation of silanolate salts, (3) judicious choice in the palladium catalyst/ligand combination, and (4) selection of the protecting group on the nitrogen of indole. It was found that the alkali metal silanolates, either isolated or formed in situ, offered a significant rate enhancement and broader substrate scope over the use of silanols activated by Bronsted bases such as NaOt-Bu. In addition, the optimized conditions for the cross-coupling of 2-indolylsilanolates were readily applied to the cross-coupling of 2-pyrrolyl-, 2-furyl-, and 2-thienylsilanolates.
