Cu-Catalyzed iminative hydroolefination of unactivated alkynes en route to 4-imino-tetrahydropyridines and 4-aminopyridines.

A general method for synthesizing 4-imino tetrahydropyridine derivatives is achieved, from readily available beta-enaminones and sulfonyl azides, which comprises a sequential copper catalyzed ketenimine formation and its hitherto inaccessible intramolecular hydrovinylation. The products are shown as ready precursors for highly valuable 4-sulfonamidopyridine derivatives via DDQ mediated oxidation.