5381-23-7Relevant academic research and scientific papers
One-Pot Regiodirected Annulations for the Rapid Synthesis of ?-Extended Oligomers
Bianchi, Gabriele,Botta, Chiara,Calcagno, Giuseppe,Etkind, Samuel I.,Nitti, Andrea,Osw, Peshawa,Pasini, Dario,Po, Riccardo,Swager, Timothy M.
supporting information, p. 3263 - 3267 (2020/04/21)
We demonstrate the broad applicability of the annulation protocol combining, in one pot, a direct arylation and cross aldol condensation for the straightforward synthesis at gram-scale of ?-extended thiophene-based scaffolds. The regiospecific direct arylation drives the subsequent cross-aldol condensation proceed under the same basic conditions, and the overall protocol has broad applicability in the synthesis of extended aromatics wherein the thiophene ring is annulated with furans, pyridines, indoles, benzothiophenes, and benzofurans. These scaffolds can be further elaborated into ?-extended, highly fluorescent oligomers with a central deficient benzothiadiazole unit with up to nine aromatic rings through coupling reactions.
Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
, p. 3860 - 3865 (2018/04/26)
Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
Synthetic Utility of Arylmethylsulfones: Annulative π-Extension of Aromatics and Hetero-aromatics Involving Pd(0)-Catalyzed Heck Coupling Reactions
Sankar, Elumalai,Raju, Potharaju,Karunakaran, Jayachandran,Mohanakrishnan, Arasambattu K.
, p. 13583 - 13593 (2017/12/26)
A straightforward and general method for the synthesis of annulated thiophene, dibenzothiophene, and carbazoles analogues has been achieved involving alkylation of 2-bromo-1-(phenylsulfonylmethyl)arene/heteroarene with arylmethyl bromides/heteroarylmethyl bromides using t-BuOK as a base in DMF, followed by Pd(0)-mediated intramolecular Heck coupling in the presence of K2CO3 in DMF at 80-140 °C. The attractive feature of this protocol is that a wide variety of π-conjugated heterocycles could be readily accessed by an appropriate choice of arylmethylsulfones and benzylic bromides.
Synthetic method of aryl halide taking aryl carboxylic acid as raw material
-
Paragraph 0133, (2018/01/03)
A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
Photocatalytic Selective Bromination of Electron-Rich Aromatic Compounds Using Microporous Organic Polymers with Visible Light
Li, Run,Wang, Zi Jun,Wang, Lei,Ma, Beatriz Chiyin,Ghasimi, Saman,Lu, Hao,Landfester, Katharina,Zhang, Kai. A. I.
, p. 1113 - 1121 (2016/02/18)
Pure organic, heterogeneous, metal-free, and visible light-active photocatalysts offer a more sustainable and environmentally friendly alternative to traditional metal-based catalysts. Here we report a series of microporous organic polymers containing photoactive conjugated organic semiconductor units as heterogeneous photocatalysts for a visible-light-promoted, highly selective bromination reaction of electron-rich aromatic compounds using HBr as a bromine source and molecular oxygen as a clean oxidant. Via a simple Friedel-Crafts alkylation reaction, the microporous organic polymers were obtained by cross-linking of organic semiconductor compounds with defined valence and conduction band positions. The utilization of the simply prepared porous polymer-based photocatalytic systems opens new opportunities toward a sustainable and efficient material design for catalysis.
Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
, p. 2794 - 2803 (2016/04/26)
Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
In-Depth Assessment of the Palladium-Catalyzed Fluorination of Five-Membered Heteroaryl Bromides
Milner, Phillip J.,Yang, Yang,Buchwald, Stephen L.
supporting information, p. 4775 - 4780 (2015/10/28)
A thorough investigation of the challenging Pd-catalyzed fluorination of five-membered heteroaryl bromides is presented. Crystallographic studies and density functional theory (DFT) calculations suggest that the challenging step of this transformation is
Lewis acid/Broensted acid mediated benz-annulation of thiophenes and electron-rich arenes
Rafiq, Settu Muhamad,Sivasakthikumaran, Ramakrishnan,Mohanakrishnan, Arasambattu K.
supporting information, p. 2720 - 2723 (2014/06/09)
A facile preparation of benz-annulated heterocycles were achieved at rt involving a Lewis acid/Broensted acid mediated annulation of heterocycles using 2,5-dimethoxytetrahydrofuran as a four-carbon synthon. The benz-/naphth-annulation was found to be successful with electron-rich arenes as well.
