Regiocontrolled Heptafluoroisopropylation of Aromatic Halides by Copper(I) Carboxylates with Heptafluoroisopropyl-Zinc Reagents

Direct electrophilic and radical isoperfluoropropylation with i-C3F7-Iodine(III) reagent (PFPI reagent)

The isoperfluoropropyl group (i-C3F7) is an emerging motif in pharmaceuticals, agrichemicals and functional materials. However, isoperfluoropropylated compounds remain largely underexplored, presumably due to the lack of efficient access to these compounds. Herein, we disclose the practical and efficient isoperfluoropropylation of aromatic C-H bonds through the invention of a hypervalent-iodine-based reagent-PFPI reagent, that proceeds via a Ag-X coupling process. The activation of the PFPI reagent without any catalysts or additives was demonstrated in the synthesis of isoperfluoropropylated electron-rich heterocycles, while its activity under photoredox catalysis was shown in the synthesis of isoperfluoropropylated non-activated arenes. Detailed mechanistic experiments and DFT calculations revealed a SET-induced concerted mechanistic pathway in the photoredox reactions. In addition, the unique conformation of i-C3F7 in products, that involved intramolecular hydrogen bond was investigated by X-ray single-crystal diffraction and variable-temperature NMR experiments.

Regioselective oxidative C–H heptafluoroisopropylation of heteroarenes with heptafluoroisopropyl silver

The regioselective C–H heptafluoroisopropylation of heteroarenes with heptafluoroisopropyl silver provided convenient access to a wide range of CF(CF3)2-containing heteroarenes.

An I(I)/I(III) Catalysis Route to the Heptafluoroisopropyl Group: A Privileged Module in Contemporary Agrochemistry

The heptafluoroisopropyl group is emerging as a privileged chemotype in contemporary agrochemistry and features prominently in the current portfolio of leading insecticides. To reconcile the expansive potential of this module with the synthetic challenges associated with preparing crowded, fluorinated motifs, I(I)/I(III) catalysis has been leveraged. Predicated on in situ generation of p-TolIF2, this route enables the direct difluorination of α-trifluoromethyl-β-difluorostyrenes in a single operation. This formal addition of fluorine across the alkene π-bond is efficient (up to 91% yield) and is compatible with a broad range of functional groups. The ArCF(CF3)2 moiety is conformationally preorganised, with the C(sp3)–F bond coplanar to the framework of the aryl ring, thereby minimising 1,3-allylic strain. Moreover, orthogonal multipolar C–F···C=O interactions have been identified in a phthalimide derivative. It is envisaged that this programmed vicinal difluorination enabled by a hypervalent iodine species will find application in functional molecule design in a broader sense.

Radical Perfluoroalkylation of Arenes via Carbanion Intermediates

The use of sodium dithionite with perfluoroalkyl iodides under basic conditions facilitates the direct perfluoroalkylation of arenes with pendant benzylic electron-withdrawing groups. This occurs via attack of the arene on the electrophilic perfluoroalkyl radical, through the donation of electron density from a benzylic anion. The substrate scope was expanded beyond benzylic nitriles with cyclic substrates bearing electron-withdrawing groups at the benzylic position-enforcing donation of electron density to the aromatic ring and enabling attack on the perfluoroalkyl radical.