Silver(I)-Catalyzed Tandem 1,3-Acyloxy Migration/Mannich-type Addition/Elimination of the Sulfonyl Group of N-Sulfonylhydrazone-propargylic Esters to 5,6-Dihydropyridazin-4-one Derivatives

The addition of nucleophiles to C?N bonds offers a highly efficient synthetic strategy for accessing nitrogen-containing molecules.1 Among the well-developed addition reactions, such as the highly efficient Mannich reaction, various C?H bond-activated compounds including carboxylic acid derivatives, nitroalkanes, and terminal alkynes have been applied as nucleophiles to achieve different classes of amines.2 However, employing new nucleophiles without activated C?H bonds, such as internal alkynes and allenic esters are limited when using metal catalysts.3 Herein, we wish to report a new addition of allenic esters to C?N bonds initiated by a silver-catalyzed 1,3-migration of propargylic esters.