A palladium‐catalyzed tandem‐cyclization of functionalized ynamides to afford a wide range of hetero‐substituted benzosultams (1,2‐benzothiazine 1,1‐dioxides) has been achieved. Medicinally useful compounds like nortriptyline and eugenol could also be used as nucleophiles. Base has a significant effect in the cyclization process, depending on the nucleophile source used. DFT studies suggest that the reaction involves a [Pd(II)]–[Pd(0)]–[Pd(II)] cycle. Structures of key products were proven by X‐ray crystallography.
