Palladium-Catalyzed Tandem-Cyclization of Functionalized Ynamides: An Approach to Benzosultams

摘要

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 nucleo-phile 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.