Ligand‐Controlled Tunable Distal C( sp ² )–H Functionalization of Aryl and Benzyl Phosphonates

Achieving regioselective C–H functionalization is a particularly difficult issue in organic chemistry when these C–H bonds have similar reactivity. Although significant progress has been made in regioselective C–H functionalization at one specific site, the tunable version of such processes is rarely documented. Here we describe a tunable meta ‐ and para ‐selective C–H borylation of aryl and benzyl phosphonates, in which the regioselectivity can be switched by bifunctional ligands. A broad range of substrates are compatible and exhibit good to excellent regioselectivity under mild reaction conditions. Benzyl phosphonates can be conveniently transformed into styrene derivatives via Horner–Wadsworth–Emmons olefination. Gram‐scale preparation and derivatization of borylated products demonstrate the important application of our method in synthetic chemistry. The orthogonality of two functional Bpin and phosphorylmethyl groups provides ample opportunity for increasing the diversity of styrene derivatives with precise site‐control.