36748-88-6Relevant articles and documents
Oxone-mediated halocyclization/demethylation of 2-alkynylthioanisoles with sodium halides towards 3-halobenzo[b]thiophenes
Chen, Xinyu,Zhang, Zhebing,Sun, Tao,Cai, Haokun,Gao, Yuzhen,Cai, Tao,Shang, Tianbo,Luo, Yanjuan,Yu, Guoqi,Shen, Hualiang,Wu, Guofeng,Hei, Yanlin,Li, Enmin,Fan, Gang
supporting information, (2022/01/14)
An efficient and practical protocol for the Oxone-mediated halocyclization/demethylation of 2-alkynylthioanisoles towards valuable 3-halobenzo[b]thiophenes is described. Structurally diverse 3-halobenzothiophenes were obtained in good to excellent yields
Nucleophilic C-H Etherification of Heteroarenes Enabled by Base-Catalyzed Halogen Transfer
Puleo, Thomas R.,Klaus, Danielle R.,Bandar, Jeffrey S.
supporting information, p. 12480 - 12486 (2021/08/24)
We report a general protocol for the direct C-H etherification of N-heteroarenes. Potassium tert-butoxide catalyzes halogen transfer from 2-halothiophenes to N-heteroarenes to form N-heteroaryl halide intermediates that undergo tandem base-promoted alcohol substitution. Thus, the simple inclusion of inexpensive 2-halothiophenes enables regioselective oxidative coupling of alcohols with 1,3-azoles, pyridines, diazines, and polyazines under basic reaction conditions.
Orthogonal Stability and Reactivity of Aryl Germanes Enables Rapid and Selective (Multi)Halogenations
Deckers, Kristina,Fricke, Christoph,Schoenebeck, Franziska
supporting information, p. 18717 - 18722 (2020/08/25)
While halogenation is of key importance in synthesis and radioimaging, the currently available repertoire is largely designed to introduce a single halogen per molecule. This report makes the selective introduction of several different halogens accessible. Showcased here is the privileged stability of nontoxic aryl germanes under harsh fluorination conditions (that allow selective fluorination in their presence), while displaying superior reactivity and functional-group tolerance in electrophilic iodinations and brominations, outcompeting silanes or boronic esters under rapid and additive-free conditions. Mechanistic experiments and computational studies suggest a concerted electrophilic aromatic substitution as the underlying mechanism.
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.
Metathesis-active ligands enable a catalytic functional group metathesis between aroyl chlorides and aryl iodides
Lee, Yong Ho,Morandi, Bill
, p. 1016 - 1022 (2018/09/06)
Current methods for functional group interconversion have, for the most part, relied on relatively strong driving forces which often require highly reactive reagents to generate irreversibly a desired product in high yield and selectivity. These approaches generally prevent the use of the same catalytic strategy to perform the reverse reaction. Here we describe a catalytic functional group metathesis approach to interconvert, under CO-free conditions, two synthetically important classes of electrophiles that are often employed in the preparation of pharmaceuticals and agrochemicals—aroyl chlorides (ArCOCl) and aryl iodides (ArI). Our reaction design relies on the implementation of a key reversible ligand C–P bond cleavage event, which enables a non-innocent, metathesis-active phosphine ligand to mediate a rapid aryl group transfer between the two different electrophiles. Beyond enabling a practical and safer approach to the interconversion of ArCOCl and ArI, this type of ligand non-innocence provides a blueprint for the development of a broad range of functional group metathesis reactions employing synthetically relevant aryl electrophiles.
Transition-Metal-Free Decarboxylative Iodination: New Routes for Decarboxylative Oxidative Cross-Couplings
Perry, Gregory J. P.,Quibell, Jacob M.,Panigrahi, Adyasha,Larrosa, Igor
supporting information, 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.
Green synthesis of benzo[b]thiophenes via iron(III) mediated 5-endo-dig iodocyclization of 2-alkynylthioanisoles
Kesharwani, Tanay,Kornman, Cory T.,Tonnaer, Amanda L.,Royappa, Andrew D.
supporting information, p. 411 - 414 (2016/01/12)
A reaction of iron(III) chloride with sodium iodide was used to generate iodine for an innovative take on electrophilic cyclization. With ethanol as solvent, the reaction was observed to provide ideal conditions for iodocyclization of 2-alkynylthioanisole
Synthesis of optically active homotryptophan and its oxygen and sulfur analogues
Goswami, Koushik,Paul, Sibasish,Bugde, Sandesh T.,Sinha, Surajit
scheme or table, p. 280 - 286 (2012/01/05)
d-Homotryptophan and its sulfur analogue have been synthesized by Sonogashira coupling between 3-iodoheteroarenes and ethynyloxazolidine followed by reduction of triple bond and oxidation of alcohol to acid. l-Homotryptophan and its oxygen analogue have b
Iodine/Palladium approaches to the synthesis of polyheterocyclic compounds
Mehta, Saurabh,Larock, Richard C.
supporting information; experimental part, p. 1652 - 1658 (2010/05/01)
Chemical Equation Represented A simple, straightforward strategy for the synthesis of polyheterocyclic compounds (PHCs) is reported, which involves iterative cycles of palladium-catalyzed Sonogashira coupling, followed by iodocyclization using I2 or ICI. A variety of heterocyclic units, including benzofurans, benzothiophenes, indoles, and isocoumarins, can be efficiently incorporated under mild reaction conditions. In addition, variations of this strategy afford a variety of linked and fused PHCs.
