Metal-free site-selective functionalization with cyclic diaryl λ³-chloranes: suppression of benzyne formation for...

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 fashions, 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 those of corresponding λ³-iodanes and λ³-bromanes, demonstrating the superiority of cyclic λ³-chloranes in ligand-coupling reactions under metal-free conditions.