Transition-Metal-Free, Intramolecular Oxidative Coupling of C(sp3)–B with C(sp2)–H

Alkylboron reagents have historically posed significant challenges in transition-metal catalysis, primarily due to the comparable electronegativities of carbon (C) and boron (B), which results in weakly polarized C-B bonds that hinder efficient transmetalation. Additionally, the propensity for β-hydride elimination further complicates the transmetalation process, limiting their applicability in synthetic transformations. In this study, we present a groundbreaking transition-metal-free strategy for the intramolecular coupling of C(sp³)-B with C(sp²)-H bonds. This innovative approach operates under mild reaction conditions, exhibits exceptional functional group compatibility, and enables the efficient construction of diverse polycyclic carbon frameworks.