Asymmetric Brønsted Acid Catalyzed Cycloadditions—Efficient Enantioselective Synthesis of Pyrazolidines, Pyrazolines, and 1,3‐Diamines from <i>N</i>‐Acyl Hyrazones and Alkenes

Abstract

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. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.