Access to (Z)-1,2-Endiamides and 1,1-Endiamides via a Base-Promoted Tandem Reaction.

An efficient base-promoted tandem reaction between vinyl 1,1-dichlorides and secondary sulfonamides with ynamide as the key intermediate is described. This method provides a facile approach to (Z)-1,2-endiamide and aryl 1,1-endiamide derivatives via the β-hydroamidation of terminal ynamides and the α-hydroamidation of internal ynamides, respectively. This reaction proceeded through double elimination of vinyl chlorides and double addition of nucleophiles to alkynes. In addition, it features readily available starting materials, mild reaction conditions, a broad substrate scope, a wide functional group tolerance, and an operational convenience.