Exploring the Catalytic Efficiency of Phosphine <i>CN</i>‐Palladacycles in the Alkoxycarbonylation of Styrene: Optimization and Scope

Abstract Five new phosphine CN ‐Palladacycles 3a‐e were synthesized, characterized, and evaluated for the reaction of alkoxycarbonylation of styrene. The efficiency of the catalytic system was influenced by the solvent, auxiliary ligand, CO pressure, reaction temperature, source and additives load (acid, salt). CN ‐palladacycle 3c with 1,3,5,7‐tetramethyl‐6‐phenyl‐2,4,8‐trioxa‐6‐phosphaadamantane (auxiliary ligand) and tert ‐butyl group on the imine fragment was the most effective pre‐catalyst for the carbonylative process. The structure of 3c was confirmed by single‐crystal X‐ray diffraction. The scope of the catalytic system with 3c was evaluated using styrene derivatives containing electron‐donating and electron‐withdrawing groups, in combination with primary, secondary, and tertiary alcohols. This evaluation generated esters with moderate to excellent yields and high regioselectivities for branched products.