Hydroboration of Enynes and Mechanistic Insights

Organoboron compounds have found broad applications in the construction of novel C−C, C−O, and C−N bonds via transition metal‐catalyzed reactions. The hydroboration of C−C multiple bonds is one of the most important methodologies to introduce the boron atom into the organic skeleton. Traditionally, boranes were employed in the hydroboration of enynes under transition metal‐free conditions. When precious metal catalysts, such as palladium and rhodium were employed in the reactions, the scope of the hydroboration, as well as the regio‐ and stereoselectivity, was improved. The asymmetric hydroboration of enynes was also achieved via Pd‐catalyzed reactions. In recent years, the non‐precious 3d‐metal catalysts, such as iron, cobalt, nickel and copper were employed in the hydroboration of enynes, especially in the enantioselective reactions. In this review, we have looked into the hydroboration of enynes as well as their mechanisms.