Selective Hydroboration of C−C Single Bonds without Transition‐Metal Catalysis

Selective hydroboration of C−C single bonds presents a fundamental challenge in the chemical industry. Previously, only catalytic systems utilizing precious metals Ir and Rh, in conjunction with N‐ and P‐ ligands, could achieve this, ensuring bond cleavage and selectivity. In sharp contrast, we discovered an unprecedented and general transition‐metal‐free system for the hydroboration of C−C single bonds. This methodology is transition‐metal and ligand‐free and surpasses the transition‐metal systems regarding chemo‐ and regioselectivities, substrate versatility, or yields. In addition, our system tolerates various functional groups such as Ar−X (X=halides), heterocyclic rings, ketones, esters, amides, nitro, nitriles, and C=C double bonds, which are typically susceptible to hydroboration in the presence of transition metals. As a result, a diverse range of γ‐boronated amines with varied structures and functions has been readily obtained. Experimental mechanistic studies, density functional theory (DFT), and intrinsic bond orbital (IBO) calculations unveiled a hydroborane‐promoted C−C bond cleavage and hydride‐shift reaction pathway. The carbonyl group of the amide suppresses dehydrogenation between the free N−H and hydroborane. The lone pair on the nitrogen of the amide facilitates the cleavage of C−C bonds in cyclopropanes. We present a general system for the hydroboration of C−C single bonds without transition‐metal catalysts. Our strategy surpasses the transition‐metal systems regarding chemo‐ and regioselectivities, substrate scopes, or yields. Mechanistic studies, DFT, and IBO calculations revealed a hydroborane‐promoted C−C bond cleavage and a hydride shift reaction pathway. The key role of the carbonyl group and the nitrogen atom of the amide was disclosed.