Metal-free homo-/cross-anion–cation coupling of cyclic diaryl λ3-bromanes

Abstract

The homo anion–cation coupling of cyclic diaryl λ³-bromanes/diarylbrominiums, which was not reported in previous reports, has been disclosed for the first time. The competition experiments indicate that the anion–cation coupling follows the nucleophilic ability of the anions: the higher the nucleophilicity, the higher the reactivity. Moreover, metal-free cross-coupling of cyclic diarylbrominium tosylates with primary/secondary/tertiary/cyclic/linear/natural alcohols, phenols, water and their deuterated forms under mild conditions has been developed, giving meta-functionalized biaryl motifs in high yields with broad substrate scope. Preliminary mechanistic studies show that the nucleophilic agent is the major proton source in the cross-anion–cation coupling, which is affected by its concentration.