Nickel‐Catalyzed Carbofluoroalkylation of 1,3‐Enynes to Access Structurally Diverse Fluoroalkylated Allenes

Dual Roles of tert-Butyl Nitrite in the Transition Metal- and External Oxidant-Free Trifluoromethyloximation of Alkenes

By employing tert-butyl nitrite as both nitrogen source and oxidant, the trifluoromethyloximation of alkenes proceeds smoothly in a free-radical process. The developed difunctionalization reaction enables practical and efficient synthesis of a wide range of α-CF₃ ketoximes in moderate yields with excellent regioselectivity. This method features the use of readily available and stable alkenes as substrates and inexpensive CF₃ SO₂ Na as a CF₃ reagent, no involvement of transition metals or external oxidant, and room-temperature conditions. Moreover, a scale-up of the reaction, further transformation of the products into various valuable CF₃ -containing compounds, and removal of the trifluoromethyl group are readily achieved.

N-Heterocyclic Carbene-Catalyzed Radical Relay Enabling Vicinal Alkylacylation of Alkenes

The N-heterocyclic carbene-catalyzed radical relay enables the vicinal alkylacylation of styrenes, acrylates and acrylonitrile using aldehydes and tertiary alkyl carboxylic acid-derived redox-active esters. This protocol introduces tertiary alkyl groups and acyl groups to C-C double bonds with complete regioselectivity to produce functionalized ketone derivatives. The radical relay mechanism involves single electron transfer from the enolate form of a Breslow intermediate and radical addition of the resultant alkyl radical to the alkene followed by radical-radical coupling.

Chlorodifluoromethane as a C1 Synthon in the Assembly of N-Containing Compounds

The development of C1 synthons to afford the products that add one extra carbon has become an important research theme in the past decade, and significant progress has been achieved with CO₂, CO, HCOOH, and others as C1 units. Despite the great advance, the search for new C1 synthons that display unique reactivity, complement to the current C1 sources, and add more value to C1 chemistry is still desirable. Herein, we report a quadruple cleavage of chlorodifluoromethane to yield a C1 source, which was successfully employed in the construction of various N-containing compounds especially with pharmaceutical molecules under mild conditions. This strategy provides a useful method for late-stage modification of pharmaceutical compounds. Four bonds in ClCF₂H were orderly cleaved under basic conditions in the absence of transition metals. Preliminary mechanistic studies revealed that (E)-N-phenylformimidoyl fluoride intermediate is involved in this process by in situ¹H NMR studies and control experiments.

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Quadruple cleavage of ClCF₂H to afford a C1 synthon

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The cleavage of two stable C(sp³)-F bonds in aliphatic gem-difluoroalkanes

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Enrich C1 chemistry, green chemistry, and fluorine chemistry

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Various N-containing compounds were afforded via different role of ClCF₂H

Selective, Intermolecular Alkylarylation of Alkenes via Photoredox/Nickel Dual Catalysis

A regioselective, intermolecular 1,2-alkylarylation of alkenes with aryl halides and alkyl oxalates has been developed via photoredox/nickel dual catalysis. This dual-catalytic protocol involves a radical relay process, where radical addition is followed by a nickel-assisted coupling, forging two consecutive C-C bonds in a single operation. The mild and redox-neutral conditions allow for good compatibility in the scope of olefins, (hetero)aryl halides, as well as alkyl oxalates.

Copper-catalyzed radical approach to allenyl iodides

A copper-catalyzed 1,4-addition reaction of arylsulfonyl iodides with 1,3-enynes afforded various allenyl halides in high yields under mild conditions via a radical mechanism.