Palladium‐Catalyzed Ring‐Forming Aminoalkenylation of Alkenes with Aldehydes Initiated by Intramolecular Aminopalladation

A palladium‐catalyzed aminopalladation reaction followed by nucleophilic addition with aldehydes and dehydration is described. This direct and operationally simple procedure provides a rapid and reliable approach to a wide range of functionalized tetrahydroisoquinolines with high selectivity. Mechanistic studies disclosed that the nucleophilic addition, performed via a highly ordered transition‐state, is the turnover‐limiting step in which the inherent β‐hydride elimination of the key Csp 3 −Pd species was controlled by the confined conformation and the nucleophilicity of the Csp 3 −Pd bond was enhanced by the strong electron‐donating effect of the nitrogen atom.