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The conversion of inexpensive aqueous ammonia (NH3·H2O) into value-added primary amines by N−H insertion persists as a longstanding challenge in chemistry because of the tendency of Lewis basic ammonia (NH3) to bind and inhibit metal catalysts. Herein, we report a chemoselective carbene N−H insertion of NH3·H2O using a TpBr3Ag-catalyzed two-phase system. Coordination by a homoscorpionate TpBr3 ligand renders silver compatible with NH3 and H2O and enables the generation of electrophilic silver carbene. Water promotes subsequent [1,2]-proton shift to generate N−H insertion products with high chemoselectivity. The result of the reaction is the coupling of an inorganic nitrogen source with either diazo compounds or N-triftosylhydrazones to produce useful primary amines. Further investigations elucidate the reaction mechanism and the origin of chemoselectivity. Converting low-cost inorganic chemicals into value-added organic chemicals is a longstanding goal in chemistry. Here the authors describe a silver-catalysed chemoselective carbene N−H insertion reaction, providing access to primary amines from aqueous ammonia and diazo compounds. [ABSTRACT FROM AUTHOR]

Here we report the sulfinylsulfonation of alkynes to afford β‐sulfinyl alkenylsulfone products with a broad substrate scope, excellent functional group compatibility, and high yield. Moreover, the sulfinylsulfonation reaction of enyne can also be realized for constructing functionalized carbo‐ and heterocycles through a radical cascade cyclization process. [ABSTRACT FROM AUTHOR]

The insertion of carbenes into the α-C–H bonds of ethers represents one of the most powerful approaches to access polysubstituted α-branched ethers. However, intermolecular carbene insertions remain challenging, since current approaches are generally limited to the use of toxic and potentially explosive α-diazocarbonyl compounds. We now report a silver-catalyzed α-C–H benzylation of ethers using bench-stable N-triftosylhydrazones as safe and convenient carbene precursors. This approach is well suited for both inter- and intramolecular insertions to deliver medicinally relevant homobenzylic ethers and 5–8-membered oxacycles in good yields. The synthetic utility of this strategy is demonstrated by its easy scalability, broad scope with valuable functional groups, high regioselectivity, and late-stage functionalization of complex oxygen-containing molecules. The relative reactivities of different types of silver carbenes and C−H bonds were also investigated by experments and DFT calculations. A state-of-the-art tool in synthetic organic chemistry is a rhodium diazocarbene species, which despite its flexibility, is derived from expensive and highly reactive species. Here the authors present a methodology for C–H benzylation of ethers via an analogous silver carbene species, obtained from a more common metal and a more stable starting material. [ABSTRACT FROM AUTHOR]

Hydrodefluorination is one of the most promising chemical strategies to degrade perfluorochemicals into partially fluorinated compounds. However, controlled progressive hydrodefluorination remains a significant challenge, owing to the decrease in the strength of C−F bonds along with the defluorination. Here we describe a carbene strategy for the sequential (deutero)hydrodefluorination of perfluoroalkyl ketones under rhodium catalysis, allowing for the controllable preparation of difluoroalkyl‐ and monofluoroalkyl ketones from aryl‐ and even alkyl‐substituted perfluoro‐alkyl ketones in high yield with excellent functional group tolerance. The reaction mechanism and the origin of the intriguing chemoselectivity of the reaction were rationalized by density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

The skeletal editing of azaarenes through insertion, deletion, or swapping of single atoms has recently gained considerable momentum in chemical synthesis. Here, we describe a practical skeletal editing strategy using vinylcarbenes in situ generated from trifluoromethyl vinyl N-triftosylhydrazones, leading to the first dearomative skeletal editing of pyrroles through carbon-atom insertion. Furthermore, depending on the used catalyst and substrate, three types of peripheral editing reactions of pyrroles are also disclosed: α- or γ-selective C-H insertion, and [3+2] cycloaddition. These controllable molecular editing reactions provide a powerful platform for accessing medicinally relevant CF 3 -containing N-heterocyclic frameworks, such as 2,5-dihydropyridines, piperidines, azabicyclo[3.3.0]octadienes, and allylated pyrroles from readily available pyrroles. Mechanistic insights from experiments and density functional theory (DFT) calculations shed light on the origin of substrate- or catalyst-controlled chemo- and regioselectivity as well as the reaction mechanism., (© 2024 Wiley-VCH GmbH.)

A silver-catalyzed regioselective defluorinative 1,3-dienylation of trifluoromethyl phenyl N-triftosylhydrazones using homoallenols as 1,3-dienyl sources provides a variety of α-(di)fluoro-β-vinyl allyl ketones with excellent functional group tolerance in moderate to good yields. The reaction proceeds through a silver carbene-initiated sequential etherification and Claisen type [3,3]-sigmatropic rearrangement cascade. The synthetic utility of this protocol was demonstrated through the downstream synthetic elaboration toward diverse synthetically useful building blocks., (© 2023 Wiley-VCH GmbH.)

Here we report a silver-catalyzed alkynyl carbene insertion into β-ketocarbonyls using alkynyl N -nosylhydrazones as alkynyl carbene precursors, which provides access to trisubstituted allenyl ketones. This reaction represents the first example of an alkynyl carbene insertion into a C-C σ bond, affording products homologated with an sp 2 carbon center. The products are useful substrates for further transformations. Experimental investigations and theoretical calculations suggest the reaction proceeds through a stepwise enol cyclopropanation/retro-aldol pathway.