Electrochemical synthesis of cyclic biaryl λ3-bromanes from 2,2'-dibromobiphenyls.

The remarkable nucleofugality of bromoarenes in diarylbromonium species renders them particularly suitable for the generation of arynes for subsequent use in a wide range of synthetic applications. The common approach to generate cyclic biaryl λ³-bromanes is based on thermal decomposition of hazardous diazonium salts. Herein, we disclose a mild and straightforward approach to diarylbromonium species by direct anodic oxidation of 2,2'-dibromo-1,1'-biphenyl. The electrochemical method provides access to a range of symmetrically and non-symmetrically substituted cyclic biaryl λ³-bromanes in moderate yields.