Metal-Free Site-Selective Functionalization with Cyclic Diaryl λ3-Chloranes: Suppression of Benzyne Formation for Ligand-Coupling Reactions

While hypervalent halogens are versatile reagents enabling diverse reactions in organic synthesis, the utility of hypervalent chlorine compounds, particularly cyclic λ3-chloranes, remains underdeveloped despite their unique electronic properties and innate enhanced reactivity. Herein, we illustrate the elusive ligand coupling reaction of cyclic λ3-chloranes that suppresses the more facile competing reaction modality involving benzyne intermediates. The methodology can be performed in three-component as well as two-component fashion, offering direct access to a wide range of unsymmetrically substituted biaryl molecules in very high yields and excellent ortho-regioselectivity. The reactions were scalable, and the versatility was demonstrated by constructing different types of C–S and C–N bonds under mild conditions. The reaction outcomes were also compared with corresponding λ3-iodanes and λ3-bromanes, demonstrating the superiority of cyclic λ3-chloranes in ligand-coupling reactions under metal-free conditions.