Electrophilic Activation of Molecular Bromine Mediated by I(III)

In pursuit of a genuine Bromo-λ3-iodane, it has been found that the combination of Br2 and electron deficient λ3-iodanes can result in delivery of both bromine atoms from Br2 to a range of aryl substrates, some highly deactivated. These brominations occur rapidly in common chlorinated solvents at room temperature and can be obtained with the catalytic activation of commercially available PhI(OAc)2 and PhI(OTFA)2. para-NO2 substituted derivatives are employed to direct bromination towards more deactivated substrates. The mechanism of Br2 activation is discussed with insights being made, however remains unclear.