28896-47-1Relevant academic research and scientific papers
Fluorocyclization of N-Propargyl Carboxamides by λ3-Iodane Catalysts with Coordinating Substituents
Takahashi, Shunsuke,Umakoshi, Yuki,Nakayama, Kaii,Okada, Yohei,Zhdankin, Viktor V.,Yoshimura, Akira,Saito, Akio
supporting information, p. 2997 - 3003 (2020/06/17)
Aiming at the enhanced catalytic activity of fluoro-λ3-iodane generated from iodoarene precatalyst with Selectfluor and HF?pyridine, this study focused on the λ3-iodanes bearing coordinating substituents. Compared to 4-iodoanisole as a precatalyst of our previous method, N-methyl-2-iodobenzamide or 2-iodobenzamide worked well in the fluorocyclization of N-propargyl carboxamides to oxazoles. Control experiments suggest the equilibrium mixture of iodane-amine complexes and cyclic iodane fluorides would be involved in the present catalysis. (Figure presented.).
Photocatalytic Oxidative Iodination of Electron-Rich Arenes
Narobe, Rok,Düsel, Simon J. S.,Iskra, Jernej,K?nig, Burkhard
supporting information, p. 3998 - 4004 (2019/07/17)
A visible-light-mediated oxidative iodination of electron-rich arenes has been developed. 2.5 mol% of unsubstituted anthraquinone as photocatalyst were used in combination with elementary iodine, trifluoroacetic acid and oxygen as the terminal oxidant. The iodination proceeds upon irradiation in non- or weakly-electron donating solvents (DCM, DCE and benzene) wherein a spectral window in strongly coloured iodine solutions can be observed at around 400 nm. The method provides good to excellent yields (up to 98%) and shows excellent regioselectivity and good functional group tolerance (triple bonds, ketone, ester, amide). Moreover, the photo-iodination was also upscaled to a 5 mmol scale (1.1 g). Mechanistic investigations by intermediate trapping and competition experiments indicate a photocatalytic arene oxidation and the subsequent reaction with iodine as a likely mechanistic pathway. (Figure presented.).
Metal-Free, Oxidant-Free, and Controllable Graphene Oxide Catalyzed Direct Iodination of Arenes and Ketones
Zhang, Jingyu,Li, Shiguang,Deng, Guo-Jun,Gong, Hang
, p. 376 - 380 (2017/12/07)
A direct, metal-free, and oxidant-free method for the graphene oxide (GO)-catalyzed iodination of arenes and ketones with iodine in a neutral medium was explored. This iodination protocol was performed by using a simple technique to avoid the use of external metal catalysts and oxidants and harsh acidic/basic reaction conditions. In addition, by this method the degree of iodination could be controlled, and the reaction was scalable and compatible with air. This strategy opens a new field for GO-catalyzed chemistry and provides an avenue for the convenient direct iodination of arenes and ketones.
Rapid Iododeboronation with and without Gold Catalysis: Application to Radiolabelling of Arenes
Webster, Stacey,O'Rourke, Kerry M.,Fletcher, Conor,Pimlott, Sally L.,Sutherland, Andrew,Lee, Ai-Lan
supporting information, p. 937 - 943 (2017/12/26)
Radiopharmaceuticals that incorporate radioactive iodine in combination with single-photon emission computed tomography imaging play a key role in nuclear medicine, with applications in drug development and disease diagnosis. Despite this importance, there are relatively few general methods for the incorporation of radioiodine into small molecules. This work reports a rapid air- and moisture-stable ipso-iododeboronation procedure that uses NIS in the non-toxic, green solvent dimethyl carbonate. The fast reaction and mild conditions of the gold-catalysed method led to the development of a highly efficient process for the radiolabelling of arenes, which constitutes the first example of an application of homogenous gold catalysis to selective radiosynthesis. This was exemplified by the efficient synthesis of radiolabelled meta-[125I]iodobenzylguanidine, a radiopharmaceutical that is used for the imaging and therapy of human norepinephrine transporter-expressing tumours.
Transition-Metal-Free Decarboxylative Iodination: New Routes for Decarboxylative Oxidative Cross-Couplings
Perry, Gregory J. P.,Quibell, Jacob M.,Panigrahi, Adyasha,Larrosa, Igor
, p. 11527 - 11536 (2017/08/30)
Constructing products of high synthetic value from inexpensive and abundant starting materials is of great importance. Aryl iodides are essential building blocks for the synthesis of functional molecules, and efficient methods for their synthesis from chemical feedstocks are highly sought after. Here we report a low-cost decarboxylative iodination that occurs simply from readily available benzoic acids and I2. The reaction is scalable and the scope and robustness of the reaction is thoroughly examined. Mechanistic studies suggest that this reaction does not proceed via a radical mechanism, which is in contrast to classical Hunsdiecker-type decarboxylative halogenations. In addition, DFT studies allow comparisons to be made between our procedure and current transition-metal-catalyzed decarboxylations. The utility of this procedure is demonstrated in its application to oxidative cross-couplings of aromatics via decarboxylative/C-H or double decarboxylative activations that use I2 as the terminal oxidant. This strategy allows the preparation of biaryls previously inaccessible via decarboxylative methods and holds other advantages over existing decarboxylative oxidative couplings, as stoichiometric transition metals are avoided.
Bronsted acidic ionic liquid accelerated halogenation of organic compounds with N-halosuccinimides (NXS)
Vrazic, Dejan,Jereb, Marjan,Laali, Kenneth K.,Stavber, Stojan
, p. 74 - 96 (2013/04/10)
The Bronsted-Acidic ionic liquid 1-methyl-3-(4-sulfobutyl) imidazolium triflate [BMIM(SO3H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into a-halo and a,a-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of a-halogenated ketone and ring-halogenated ketones were obtained. Activated aromatics were regioselectively ring halogenated to give mono- and dihalo-substituted products. The [BMIM(SO3H)][OTf] ionic liquid (IL-A) was successfully reused eight times in a representative monohalogenation reaction with no noticeable decrease in efficiency. An effective halogenation scale-up in this IL is also presented. The reactivity trend and the observed chemo- and regioselectiivities point to an ET process in these IL-promoted halofunctionalization reactions.
A convenient alumination of functionalized aromatics by using the frustrated Lewis pair Et3Al and TMPMgCl·LiCl
Unsinn, Andreas,Wunderlich, Stefan H.,Jana, Anukul,Karaghiosoff, Konstantin,Knochel, Paul
supporting information, p. 14687 - 14696 (2013/11/06)
A straightforward and efficient alumination of functionalized arenes by using the frustrated Lewis pair Et3Al and TMPMgCl×LiCl (TMP=2,2,6,6-tetramethylpiperidyl) has been developed. In particular, halogenated electron-rich aromatics can be smoothly functionalized by using the frustrated Lewis pair Et3Al and TMPMgCl×LiCl. Compared with previously described alumination methods, this procedure avoids extensive cooling and the need for an excess of base. This in situ procedure has proven to be most practical and allows for regio- and chemoselective metalation of a wide range of aromatics with sensitive functional groups (CONEt2, CO 2Me, CN, OCONMe2) or halogens (F, Cl, Br, I). The resulting aromatic aluminates, which were characterized by using NMR spectroscopy, were subjected to allylations, acylations, and palladium-catalyzed cross-coupling reactions after transmetalation to zinc. It was shown that the nature of the Zn salt used for transmetalation is crucial. Thus, compared with ZnCl2 (2equiv), the use of Zn(OPiv)2 (2equiv; OPiv=pivalate) allows the subsequent quenching reactions to be performed with only a slight excess of electrophile (1.2equiv) and provides interesting functionalized aromatics in good yields.
Hypervalent iodine(III)-LiX combination in fluoroalcohol solvent for aromatic halogenation of electron-rich arenecarboxylic acids
Hamamoto, Hiromi,Hattori, Sho,Takemaru, Kaori,Miki, Yasuyoshi
scheme or table, p. 1563 - 1566 (2011/08/03)
The novel reagent system, PhI(OAc)2-LiX combination in fluoroalcohol solvents, was found to be effective for halodecarboxylation of electron-rich arenecarboxylic acids. The method provided an efficient route to halogenated phenol ether derivatives. Georg Thieme Verlag Stuttgart ? New York.
Desulfonyloxyiodination of arenesulfonic acids with mCPBA and molecular iodine
Suzuki, Yuhsuke,Ishiwata, Yoshihide,Moriyama, Katsuhiko,Togo, Hideo
experimental part, p. 5950 - 5953 (2010/11/21)
Treatment of p-alkylbenzenesulfonic acids with mCPBA and molecular iodine gave p-alkyliodobenzenes in good to moderate yields via electrophilic ipso-substitution by the iodonium species (I+) formed. This desulfonyloxyiodination was promoted by the addition of a catalytic amount of iodoarenes, such as o-iodobenzoic acid. The same treatment of dimethylbenzenesulfonic acids and trimethylbenzenesulfonic acids with mCPBA and molecular iodine proceeded smoothly both in the absence and in the presence of o-iodobenzoic acid to provide the corresponding monoiodo-dimethylbenzene and diiodo-dimethylbenzene, and diiodo-trimethylbenzene and triiodo- trimethylbenzene, in good to moderate yields, respectively. On the other hand, the same desulfonyloxyiodination of benzenesulfonic acid and p-chlorobenzenesulfonic acid with mCPBA and molecular iodine proceeded only in the presence of o-iodobenzoic acid to generate iodobenzene and p-chloroiodobenzene, respectively, in moderate yields.
METHOD OF PRODUCING IODIZING AGENT, AND METHOD OF PRODUCING AROMATIC IODINE COMPOUND
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Page/Page column 10, (2010/05/13)
A method of the present invention, for producing an iodizing agent, includes the step of electrolyzing iodine molecules in a solution by using an acid as a supporting electrolyte. This realizes (i) a method of producing an iodine cation suitable for use as an iodizing agent that does not require a sophisticated separation operation after iodizing reaction is completed, and (ii) an electrolyte used in the method. Further, a method of the present invention, for producing an aromatic iodine compound, includes the step of causing an iodizing agent, and an aromatic compound whose nucleus has one or more substituent groups and two or more hydrogen atoms, to react with each other under the presence of a certain ether compound. This realizes such a method of producing an aromatic iodine compound that position selectivity in iodizing reaction of an aromatic compound is improved.
