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We highlight key contributions in the field of direct radical CAr− H (hetero)aromatic functionalization involving fluorinated radicals. A compilation of Functional Group Transfer Reagents and their diverse activation mechanisms leading to the release of radicals are discussed. The substrate scope for each radical is analyzed and classified into three categories according to the electronic properties of the substrates. Density functional theory computational analysis provides insights into the chemical reactivity of several fluorinated radicals through their electrophilicity and nucleophilicity parameters. Theoretical analysis of their reduction potentials also highlights the remarkable correlation between electrophilicity and oxidizing ability. It is also established that highly fluorinated radicals (e.g. ⋅OCF3) are capable of engaging in single‐electron transfer (SET) processes rather than radical addition, which is in good agreement with experimental literature data. A reactivity scale, based on activation barrier of addition of these radicals to benzene is also elaborated using the high accuracy DLPNO‐(U)CCSD(T) method. [ABSTRACT FROM AUTHOR]

Nitroaromatic compounds represent one of the essential classes of molecules that are widely used as feedstock for the synthesis of intermediates, the preparation of nitro‐derived pharmaceuticals, agrochemicals, and materials on both laboratory and industrial scales. We herein disclose the efficient, mild, and catalytic ipso‐nitration of organotrimethylsilanes, enabled by an electrophilic N‐nitrosaccharin reagent and allows chemoselective nitration under mild reaction conditions, while exhibiting remarkable substrate generality and functional group compatibility. Additionally, the reaction conditions proved to be orthogonal to other common functionalities, allowing programming of molecular complexity via successive transformations or late‐stage nitration. Detailed mechanistic investigation by experimental and computational approaches strongly supported a classical electrophilic aromatic substitution (SEAr) mechanism, which was found to proceed through a highly ordered transition state. [ABSTRACT FROM AUTHOR]

Herein, we introduce an electrochemically assisted generation of nitryl radicals from ferric nitrate under mild reaction conditions using a simple setup with inexpensive graphite and stainless‐steel electrodes. The mechanism of the reaction is supported by detailed spectroscopic and experimental studies. Powered by electricity and driven by electrons, the synthetic diversity of this reaction has been demonstrated through the development of highly efficient nitration protocols of various unsaturated hydrocarbons. In addition to a broad application area, these protocols are easy to scale for decagram quantities, and exhibit exceptional substrate generality and functional‐group compatibility. [ABSTRACT FROM AUTHOR]

The incorporation of the gem‐difluoromethylene (CF2) group into organic frameworks is highly sought due to the influence of this unit on the physicochemical and pharmacological properties of molecules. Herein we report an operationally simple, mild, and switchable protocol to access various gem‐difluoro compounds that employs chlorodifloroacetic anhydride (CDFAA) as a low‐cost and versatile fluoroalkylating reagent. Detailed mechanistic studies revealed that electron‐transfer photocatalysis triggers mesolytic cleavage of a C−Cl bond generating a gem‐difluoroalkyl radical. In the presence of alkene, this radical species acts as a unique intermediate that, under solvent‐controlled reaction conditions, delivers a wide range of gem‐difluorinated γ‐lactams, γ‐lactones, and promotes oxy‐perfluoroalkylation. These protocols are flow‐ and batch‐scalable, possess excellent chemo‐ and regioselectivity, and can be used for the late‐stage diversification of complex molecules. [ABSTRACT FROM AUTHOR]

What a couple! Arenes functionalized with donating groups undergo oxidative dehydrogenative coupling with alcohols in the presence of a copper/silver catalyst system. This intermolecular CH alkoxylation provides a convenient synthetic route to the important class of aryl ethers. The catalyst system also allows the alkoxylation of benzylic CH groups with formation of benzyl alkyl ethers. [ABSTRACT FROM AUTHOR]

We report a mild and operationally simple trifluoroacylation strategy of olefines, that utilizes trifluoroacetic anhydride as a low‐cost and readily available reagent. This light‐mediated process is fundamentally different from conventional methodologies and occurs through a trifluoroacyl radical mechanism promoted by a photocatalyst, which triggers a C−O bond fragmentation. Mechanistic studies (kinetic isotope effects, spectroelectrochemistry, optical spectroscopy, theoretical investigations) highlight the evidence of a fleeting CF3CO radical under photoredox conditions. The trifluoroacyl radical can be stabilized under CO atmosphere, delivering the trifluoroacetylation product with higher chemical efficiency. Furthermore, the method can be turned into a trifluoromethylation protocol by simply changing the reaction parameters. Beyond simple alkenes, this method allows for chemo‐ and regioselective functionalization of small‐molecule drugs and common pharmacophores. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and characterization of a hypervalent‐iodine‐based reagent that enables a direct and selective nitrooxylation of enolizable C−H bonds to access a broad array of organic nitrate esters is reported. This compound is bench stable, easy‐to‐handle, and delivers the nitrooxy (‐ONO2) group under mild reaction conditions. Activation of the reagent by Brønsted and Lewis acids was demonstrated in the synthesis of nitrooxylated β‐keto esters, 1,3‐diketones, and malonates, while its activity under photoredox catalysis was shown in the synthesis of nitrooxylated oxindoles. Detailed mechanistic studies including pulse radiolysis, Stern–Volmer quenching studies, and UV/Vis spectroelectrochemistry reveal a unique single‐electron‐transfer (SET)‐induced concerted mechanistic pathway not reliant upon generation of the nitrate radical. [ABSTRACT FROM AUTHOR]

Demonstrated herein is the construction of trifluoromethylated quaternary carbon centers by an asymmetric radical transformation. Enantioenriched trifluoromethylated oxindoles were accessed using a hypervalent iodine‐based trifluoromethyl transfer reagent in combination with a magnesium Lewis acid catalyst and PyBOX‐type ligands to achieve up to 99 % ee and excellent chemical yields. Mechanistic studies were performed by experimental and computational methods and suggest a single‐electron transfer induced SN2‐type mechanism. This example is thereby the first report on the construction of enantioenriched trifluoromethylated carbon centers using hypervalent iodine‐based reagents proceeding through such a reaction pathway. Taming the CF3 radical: A unique single‐electron transfer (SET) induced SN2‐type reaction enables the construction of enantioenriched trifluoromethylated oxindoles using a hypervalent iodine‐based trifluoromethyl transfer reagent. A combination of magnesium Lewis acid catalysis and PyBOX‐type ligands successfully tames the highly reactive CF3 radical to achieve excellent enantioselectivities. [ABSTRACT FROM AUTHOR]