Asymmetric Brønsted Acid Catalyzed Cycloadditions—Efficient Enantioselective Synthesis of Pyrazolidines, Pyrazolines, and 1,3-Diamines from N-Acyl Hyrazones and Alkenes


  • M.S.M. thanks the Alexander von Humboldt Foundation, and H.B.K. thanks The Council of Higher Education of Turkey for a fellowship.


original image

A general, metal-free, highly enantioselective Brønsted acid catalyzed [3+2] cycloaddition between hydrazones and alkenes has been developed that affords pyrazolidine derivatives (see scheme). The resulting optically active pyrazolidines can undergo many chemical transformations which allow, for example, the enantioselective synthesis of valuable pyrazolines and 1,3-diamines.