Light-mediated copper-catalyzed phosphorus/halogen exchange in 1,1-difluoroalkylphosphonium salts.

A method for the assembly of the halodifluoromethyl group (CF2X, X = Cl, Br, I) is described. The reaction involves the light-mediated substitution of the triphenylphosphine by halide anions in readily accessible gem-difluorinated phosphonium salts.

Visible light-mediated difluoroalkylation of electron-deficient alkenes.

A method for the reductive difluoroalkylation of electron-deficient alkenes using 1,1-difluorinated iodides mediated by irradiation with blue light is described. The reaction involves radical addition of 1,1-difluorinated radicals at the double bond followed by hydrogen atom transfer from sodium cyanoborohydride.

Photocatalytic Reductive Fluoroalkylation of Nitrones.

A method for the addition of fluorinated groups to nitrones using an iridium photocatalyst and ascorbic acid as a stoichiometric reducing agent is described. The reaction proceeds through the generation of fluorinated radicals by single-electron reduction of fluorinated alkyl iodides with an iridium complex mediated by visible light. Besides perfluorinated reagents, partially fluorinated alkyl iodides can also be effectively used leading to the products, which cannot be obtained by conventional nucleophilic addition reactions.

Copper-Catalyzed Coupling of Acyl Chlorides with gem-Difluorinated Organozinc Reagents via Acyl Dithiocarbamates.

A cross-coupling of acyl chlorides with gem-difluorinated organozinc reagents affording difluorinated ketones is described. In the reaction, acyl chlorides are first treated with potassium dithiocarbamate to generate S-acyl dithiocarbamates, which couple with organozincs in the presence of a copper(I) catalyst.

Synthesis of 3-Fluoropyridines via Photoredox-Mediated Coupling of α,α-Difluoro-β-iodoketones with Silyl Enol Ethers.

A method for the synthesis of diversely substituted 3-fluoropyridines from two ketone components is described. The reaction involves photoredox coupling of α,α-difluoro-β-iodoketones with silyl enol ethers catalyzed by fac-Ir(ppy) under blue LED irradiation with subsequent one-pot condensation with ammonium acetate. Based on cyclic voltammetry studies, it was determined that α,α-difluoro-β-iodoketones are reduced notably easier compared to 2,2,2-trifluoro-1-iodoethane, which may be ascribed to the influence of the carbonyl group.