Single-electron-transfer (SET)-induced oxidative biaryl coupling by polyalkoxybenzene-derived diaryliodonium(III) salts.

Metal-free oxidative C-C coupling by using polyalkoxybenzene-derived diaryliodonium(III) salts as both the oxidant and aryl source has been developed. These salts can induce single-electron-transfer (SET) oxidation to yield electron-rich arenes and subsequently transfer the polyalkoxyphenyl group into in situ generated aromatic radical cations to produce biaryl products. The reaction is promoted by a Lewis acid that activates the iodonium salts. It has been revealed that the reactivity of the salts under acidic conditions is quite different to their known behavior under basic conditions. The reactivity preference of a series of iodonium salts in the SET oxidation and their ligand transfer abilities have been systematically investigated and the results are summarized in this report.

Organocatalytic C­H/C­H' cross-biaryl coupling: C-selective arylation of sulfonanilides with aromatic hydrocarbons.

The hypervalent iodine-mediated C-C selective coupling of N-methanesulfonyl anilides with aromatic hydrocarbons has been developed. The first organocatalytic oxidative cross-biaryl-coupling was achieved by the catalyst control in defining specific 2,2'-diiodobiphenyls for the direct C-C bond formations.

Synthesis of boron-substituted diaryliodonium salts and selective transformation into functionalized aryl boronates.

Dormant boron awaits its true destiny in diaryliodonium salts synthesized from aryl boronate derivatives according to two alternative general methods with hypervalent iodine(III) reagents and fluoroalcohol solvents: transformation of an aryl C-H bond and boron-iodine(III) exchange (see scheme; FG = functional group). The salts could be functionalized by both catalyst-free and metal-catalyzed reactions without loss of the boron functionality.

Metal-free C-H cross-coupling toward oxygenated naphthalene-benzene linked biaryls.

The intermolecular C-H cross-coupling between aromatic ethers has been achieved for the first time using perfluorinated hypervalent iodine(III) compounds as extreme single-electron-transfer (SET) oxidants. The demonstrations of this specific coupling could provide a direct route to valuable oxygenated mixed naphthalene-benzene biaryls 3 only, without formation of other biaryl-derived byproducts.