Easy, inexpensive and effective oxidative iodination of deactivated arenes in sulfuric acid

Two ‘model’ deactivated arenes, benzoic acid and nitrobenzene, were effectively monoiodinated within 1 h at 25-30 °C, with strongly electrophilic I⁺ reagents, prior prepared from diiodine and various oxidants (CrO₃, KMnO₄, active MnO₂, HIO₃, NaIO₃, or NaIO₄) in 90% (v/v) concd sulfuric acid (ca. 75 mol% H₂SO₄). Next, an I₂/NaIO₃/90% (v/v) concd H₂SO₄ exemplary system was used to effectively mono- or diiodinate a number of deactivated arenes. All former papers dealing with the direct iodination of deactivated arenes are briefly reviewed.     

Triolborates: water-soluble complexes of arylboronic acids as precursors to iodoarenes

A facile synthesis of aryl and heteroaryl iodides from water-soluble complexes of aryl- and heteroarylboronic acids has been developed.     

Reaction of iodoarenes with potassium peroxodisulfate/trifluoroacetic acid in the presence of aromatics. Direct preparation of diaryliodonium triflates from iodoarenes

Diaryliodonium triflates have been directly prepared by reaction of some iodoarenes with aromatic substrates in good yields by using K₂S₂O₈/CF₃COOH/CH₂Cl₂. Treatment of a variety of iodoarenes with iodobenzene under the same conditions resulted in ligand transfer, and (4-iodophenyl)(phenyl)iodonium triflate was obtained. This procedure avoids the use of high temperature and severe reaction conditions.     

A solvent-free synthesis of (dichloroiodo)arenes from iodoarenes

An efficient solid-state oxidation of iodoarenes, ArI, is described using the urea-hydrogen peroxide adduct (UHP), a stable, inexpensive, and easily handled oxidant. The reactions were complete in 15 min at 85 °C. The melts thus obtained were reacted with excess hydrochloric acid to afford crude (dichloroiodo)arenes, ArICl₂, in 64-98% yields.