Radical Borylation of Aryl Sulfones with an NHC-Borane: A Modular Approach to Aryl Boranes

Aryl boron compounds are central to modern synthetic chemistry, yet their preparation often relies on transition meta l catal-ysis or reactive organometallic intermediates. Here we report a transition-metal-free method for the synthesis of aryl bo-ranes via the radical borylation of aryl sulfones using 1,3-dimethylimidazol-2-ylidene borane (diMeImd–BH₃). This transfor-mation proceeds via nucleophilic addition of an NHC–boryl radical to the sulfone, followed by β-scission to deliver the aryl bo-rane and a sulfonyl radical. The resulting aryl boranes are amenable to iterative Suzuki–Miyaura cross-coupling, enabling efficient access to oligomeric aryl frameworks. These findings expand the synthetic utility of boryl radicals and offer a modular platform for arene functionalization.