Dual Photoredox/Copper Catalyzed Fluoroalkylative Alkene Difunctionalization

TBHP-Promoted Trifluoromethyl-difluoromethylthiolation of Unactivated Alkenes with CF3SO2Na and PhSO2SCF2H

A TBHP-promoted trifluoromethyl-difluoromethylthiolation of alkenes was reported. Langlois' reagent was used as a stable and inexpensive trifluoromethyl source. In the presence of TBHP, the trifluoromethyl radical generated reacted with alkenes, achieving a new alkyl radical, which could be trapped by PhSO2SCF2H, forming C-C and C-S bonds in one step and incorporating trifluoromethyl and difluoromethylthio groups. The mild conditions and broad functional group tolerance endowed the reaction with great potential in the field of pharmaceuticals and agrochemicals.

From S-Fluoroalkylation to Fluoroalkylation-Thiolation: Difunctionalization of Alkenes with Fluoroalkyl Phenyl Sulfones and Thiophenols Enabled by Photoredox Copper Catalysis

Molecules containing fluoroalkyl and arylthio groups play a pivotal role in pharmaceutical and agrochemical development. The simultaneous introduction of these functional groups through the 1,2-difunctionalization of alkenes is an efficient strategy. Fluoroalkyl phenyl sulfones serve as accessible fluoroalkyl radical precursors; however, their tendency to interact with thiophenol via the electron donor-acceptor interaction mechanism can impede the desired transformation. Through meticulous selection of solvent and base, we successfully utilized copper catalysis to facilitate an alkene-involved three-component reaction. Our work unveils a photoredox copper-catalyzed fluoroalkylation-thiolation of alkenes using various fluoroalkyl phenyl sulfones (such as perfluoroethyl, tetrafluoroethyl, trifluoromethyl, difluoromethyl, difluoroalkyl, and difluorobenzyl). The efficacy of this approach is exemplified by the synthesis of Kengreal derivatives.

Better Together: Photoredox/Copper Dual Catalysis in Atom Transfer Radical Polymerization

Photomediated Atom Transfer Radical Polymerization (photoATRP) is an activator regeneration method, which allows for the controlled synthesis of well-defined polymers via light irradiation. Traditional photoATRP is often limited by the need for high-energy ultraviolet or violet light. These could negatively affect the control and selectivity of the polymerization, promote side reactions, and may not be applicable to biologically relevant systems. This drawback can be circumvented by an introduction of the catalytic amount of photocatalysts, which absorb visible and/or NIR light and, therefore, controlled, regenerative ATRP can be performed with the dual-catalytic cycle. Herein, a critical summary of recent developments in the field of dual-catalysis concerning Cu-catalyzed ATRP is provided. Contributions of involved species are examined mechanistically, followed by challenges and future directions towards the next generation of advanced functional macromolecular materials.

Dual ligand-enabled iron and halogen-containing carboxylate-based photocatalysis for chloro/fluoro-polyhaloalkylation of alkenes

Herein, we demonstrate a practical dual ligand-enabled iron photocatalysis paradigm-converting all kinds of halogen-containing carboxylates (C n X m COO-, X: F, Cl, Br) into C n X m radicals for the valuable chloro/fluoro-polyhaloalkylation of non-activated alkenes with easily available trichloroacetonitrile/Selectfluor as the electrophilic halogenation reagent. The modular in situ assembly of the effective iron and C n X m COO--based light-harvesting species using the two ligands-OMe/CF3-substituted bipyridine and acetonitrile/trichloroacetonitrile is evidenced by detailed mechanistic studies. The late-stage modification, low loading amount of iron (TON: 257) and feasible gram-scale synthesis show the utility of this protocol. We thus anticipate that the dual ligand-enabled iron photocatalysis paradigm may facilitate activation and transformation of inert bulk chemicals.

Photodriven Radical Perfluoroalkylation-Thiolation of Unactivated Alkenes Enabled by Electron Donor-Acceptor Complex

A clean and direct three-component radical 1,2-difunctionalization of various alkenes with perfluoroalkyl iodides and thiosulfonates enabled by the electron donor-acceptor complex has been developed under light illumination at room temperature. The approach offers a convenient and environmentally friendly route for the simultaneous incorporation of Csp3-Rf and Csp3-S bonds, affording valuable polyfunctionalized alkane derivatives containing fluorine and sulfur in satisfactory yields. Consequently, this methodology holds significant value and practicality in the field of organic synthesis.

Photo-induced 1,2-thiohydroxylation of maleimide involving disulfide and singlet oxygen

A visible light-driven di-functionalization of maleimide with disulfide and in situ-generated singlet oxygen offers selective 1,2-thiohydroxylation under additive-free conditions. Here the disulfide plays the dual role of photosensitizer and the coupling reagent. Notably, the hydroxyl functionality originates from the in situ generated singlet oxygen followed by HAT from H2O (moisture).