Three-Component Alkyl-Diborylmethylation of Alkenes Enabled by Dual Photoredox/Copper Catalysis

A photoredox-catalyzed strategy has been developed for the three-component dicarbofunctionalization of alkenes with aliphatic <i>N</i>-hydroxyphthalimide esters and (diborylmethyl)zinc species under dual photoredox/copper catalysis. This protocol enables direct access to structurally unique and synthetically valuable C(sp³)-rich <i>gem</i>-diborylalkanes. The reaction proceeds under mild conditions and features a broad substrate scope, including primary, secondary, and tertiary carboxylic acids, while also demonstrating excellent scalability and practical utility. Mechanistic studies support a radical relay pathway involving radical addition, followed by diborylmethyl Cu(I)-mediated C(sp³)-C(sp³) cross-coupling.