Practical Electrochemical Iodination of Aromatic Compounds

A practical method for electrochemical iodination of aromatic compounds was developed. The method involves the generation of I+ by electrochemical oxidation of I-2 in CH3CN using H2SO4 as supporting electrolyte followed by the reaction with aromatic compounds. The para/ortho selectivity for the reaction of monosubstituted benzenes was significantly improved using dimethoxyethane as cosolvent in the second step. The reaction with highly reactive aromatic compounds led to the formation of significant amounts of diiodo compounds in a macrobatch reactor. This problem was solved by fast 1:1 mixing of I+ with an aromatic compound using a microflow system consisting of a T-shaped micromixer and a microtube reactor.