Boryl (Hetero)aryne Precursors as Versatile Arylation Reagents: Synthesis through C-H Activation and Orthogonal Reactivity

Abstract

(Pinacolato)boryl ortho-silyl(hetero)aryl triflates are presented as a new class of building blocks for arylation. They demonstrate unique versatility by delivering boronate or (hetero)aryne reactivity chemoselectively in a broad range of transformations. This approach enables the unprecedented postfunctionalization of fluoride-activated (hetero)aryne precursors, for example, as substrates in transition-metal catalysis, and offers valuable new possibilities for aryl boronate postfunctionalization without the use of specialized protecting groups. Ready for a complete makeover: As building blocks for arylation, (pinacolato)boryl ortho-silyl (hetero)aryl triflates (see structure; X=C, N) showed unique versatility by reacting chemoselectively as boronates or (hetero)arynes in a broad range of transformations. This approach offers valuable possibilities for the functionalization of both aryne precursors and aryl boronates without the use of specialized protecting groups.