Cross-Dehydrogenative Coupling of Ligated Boranes with Aldehydes for the Direct Synthesis of Acylboranes.

Acylboranes are valuable building blocks in synthesis and bioconjugation, yet their preparation remains challenging. We report the first transition-metal-free cross-dehydrogenative coupling of aldehydes with ligated boranes, providing direct access to acylboranes under mild oxidative conditions. The reaction exhibits a broad substrate scope and functional group tolerance, and mechanistic studies support a radical pathway. The resulting acylboranes undergo diverse downstream transformations, including Suzuki coupling, homologation, and amination, highlighting the versatility and synthetic utility of this approach.