Substrate-Controlled Co-MHAT Catalyzed 1,4- and 1,2-Hydropyridination of 1,3-Enynes

The unique structure of 1,3-enyne endows it with various reactivities in organic synthesis. In the past decades, via a radical process, great progress has been made in the 1,2- and 1,4-difunctionalization of 1,3-enynes. However, the 1,2- and 1,4-hydrofunctionalization of 1,3-enynes has been studied less. Herein, we report a reductive Co-MHAT-catalyzed 1,4- and 1,2-hydropyridination of 1,3-enynes, providing efficient access to valuable propargylpyridines and allenylpyridines from the readily available starting material. Furthermore, a wide substrate scope for 1,3-enynes, excellent functional group compatibility, and the antiproliferative activity for these novel allenylpyridines demonstrated that this method has significant application in medicinal chemistry.