Cyclic Diaryl λ3-Bromanes as Original Aryne Precursors

Despite the widespread application of hypervalent iodines, the corresponding lambda(3)-bromanes are less explored. Herein we report a general, safe, and high-yielding strategy to access cyclic diaryl lambda(3)-bromanes. These unique compounds feature reactivity that is appealing and complementary to that of lambda(3)-iodanes, generating arynes under mild reaction conditions and in the presence of a weak base. Accordingly, formal meta-selective transition-metal-free C-O and C-N couplings may be achieved. Mechanistic studies unambiguously support the aryne generation mechanism.

Automated summary

A general, safe, and high-yielding strategy to access cyclic diaryl lambda(3)-bromanes is reported in this study, featuring reactivity complementary to that of lambda(3)-iodanes to generate arynes under mild reaction conditions in the presence of a weak base. Mechanistic studies unambiguously support the aryne generation mechanism.