Pd-Catalyzed C–O Bond Formation: Coupling of Aryl Boronic Acids with O-Electrophiles

Due to the scarcity of practically useful O-electrophiles, Suzuki-type C–O coupling is far less common than the well-established C–C coupling. In this work, we introduce cyclic diacyl peroxides as effective O-electrophiles for cross-coupling with boronic acids, a process that likely proceeds via a Pd(II)/Pd(IV) catalytic cycle. The success of this method can be attributed to the higher oxidative potential of cyclic diacyl peroxides and the ability to avoid the elimination of CO₂ in high-valent Pd intermediates. Additionally, the Pd(IV) complex with cyclic diacyl peroxide maintains a ground state singlet spin state with no radical character on the acetate and carboxylate ligands that facilitate the transmetalation step. The reaction produces a variety of aryl esters with an additional carboxylic acid group as a platform for further functionalization.