Abstract
In sharp contrast to hypervalent iodine(III) compounds, the isoelectronic bromine(III) counterparts have been little studied to date. This knowledge gap is mainly attributed to the difficult-to-control reactivity of λ(3) -bromanes as well as to their challenging preparation from the highly toxic and corrosive BrF(3) precursor. In this context, we present a straightforward and scalable approach to chelation-stabilized λ(3) -bromanes by anodic oxidation of parent aryl bromides possessing two coordinating hexafluoro-2-hydroxypropanyl substituents. A series of para-substituted λ(3) -bromanes with remarkably high redox potentials spanning a range from 1.86 V to 2.60 V vs. Ag/AgNO(3) was synthesized by the electrochemical method. We demonstrate that the intrinsic reactivity of the bench-stable bromine(III) species can be unlocked by addition of a Lewis or a Brønsted acid. The synthetic utility of the λ(3) -bromane activation is exemplified by oxidative C-C, C-N, and C-O bond forming reactions.