Palladium-Catalyzed α-Arylation of Esters: Synthesis of the Tetrahydroisoquinoline Ring

The palladium-catalyzed cross-coupling reaction used for carbon–carbon bond formation is one of the most commonly applied reactions in modern organic synthesis. In this work, a concise strategy was developed for constructing the tetrahydroisoquinoline core, a key structural motif found in many biologically active compounds. This method involves the palladium-catalyzed intramolecular coupling of aryl iodides with ester enolates generated in the presence of K3PO4 as a base, resulting in the formation of the tetrahydroisoquinoline ring with an exceptionally high yield of 84%.