Photo/Ni dual-catalyzed radical defluorinative sulfonylation to synthesize gem-difluoro allylsulfones

Visible Light Photoredox-Catalyzed Radical Defluorinative Arylation of α-Trifluoromethyl Alkenes with Aryl Chlorides

Photocatalytic defluorinative cross-coupling reactions of α-trifluoromethyl alkenes with diverse radical precursors have emerged as a powerful strategy for the synthesis of gem-difluoroalkenes. However, the radical defluorinative arylation is relatively rare due to the limitation of aryl radical precursors. Aryl chlorides, as ideal candidates, remain a large challenge in this reaction because of the chemical inertness of the C(sp2)-Cl bond and their high negative reduction potential. Herein, we report a radical defluorinative arylation of α-trifluoromethyl alkenes with aryl chlorides as aryl radical precursors through a consecutive photoinduced electron transfer (ConPET) process. This protocol features mild conditions, operational simplicity, wide substrate scope, and functional group tolerance, producing a diverse range of benzylic gem-difluoroalkenes in moderate to good yields. The scale-up reaction and the valuable transformations of products demonstrate the great potential applications of this approach.

Three-Component Sulfonylation and Heteroannulation Enabled by 3-Fold Defluorofunctionalization of Trifluoromethyl Enones

Trifluoromethyl enone emerges as a versatile and multifaceted building block in organic synthesis. A defluorinative heterocyclization reaction of readily available β,β-ditrifluoromethylated enones and biocompatible sodium sulfinates has been developed for the modular synthesis of densely functionalized furans with regio-defined C2,4-bissulfonyl and C3-trifluoromethyl substitutions. This three-component method proceeds through a sequential sulfonylation and intramolecular O-cyclization, enabling the assembly of one furan ring, the formation of C-SO2/C-O bonds, and the cleavage of three C(sp3)-F bonds in a one-pot manner under transition metal-free conditions. Moreover, the obtained furan product can further react with a benzyne precursor to generate 1,4-epoxynaphthalene through a Diels-Alder cycloaddition. The reaction is also distinguished by its broad substrate scope, excellent functional group tolerance, and scalability.

Hydroazidation of trifluoromethyl alkenes with trimethylsilyl azide enabled by organic photoredox catalysis

Herein, we report an organic photoredox-catalyzed hydroazidation of trifluoromethyl alkenes with user-friendly trimethylsilyl azide (TMSN3), enabling a direct access to a broad range of valuable β-CF3-azides with exclusive selectivity under mild reaction conditions. The synthetic utility of this reaction was demonstrated by the late-stage modification of complex drug derivatives, scale-up of the reaction and diverse further derivatizations of the β-CF3-azide product.

Synthesis of gem-Difluorohomoallyl Amines via a Transition-Metal-Free Defluorinative Alkylation of Benzyl Amines with Trifluoromethyl Alkenes

A mild and transition-metal-free defluorinative alkylation of benzyl amines with trifluoromethyl alkenes is reported. The features of this protocol are easy-to-obtain starting materials, a wide range of substrates, and functional group tolerance as well as high atom economy, thus offering a strategy to access a variety of gem-difluorohomoallyl amines, which are extensively distributed in pharmaceuticals and bioactive agents, with excellent chemoselectivity. The primary products can be further transformed to a diversity of 2-fluorinated pyrroline compounds.

Photoredox Enabled Defluorinative Benzylation of Trifluoromethyl Alkenes with Alkylarenes

Herein, we report a photoredox enabled defluorinative benzylation of trifluoromethyl alkenes with readily available alkylarenes, which provides convenient access to a series of structurally valuable benzylated gem-difluoroalkenes under mild reaction conditions. The synthetic value of this protocol has been demonstrated by the transformations of several substrates bearing drug moieties, gram-scale reactions, and various further derivatizations of the gem-difluoroalkene products. The preliminary mechanistic investigations suggest a reaction pathway with rate-determining benzyl C-H bond cleavage of toluene followed by benzylic radical formation.