Catalytic and catalyst-free diboration of alkynes

The diboration of alkynes has become the most straightforward and powerful method for the synthesis of functionalized 1,2-diborylalkenes, which are widely used as building blocks in organic synthesis. The present review provides a comprehensive summary of the diboration of alkynes, including platinum-, palladium-, cobalt-, copper-, iridium-, gold-, iron-, base- and small organic molecule-catalyzed diboration, direct and metal-free diboration, and base- promoted diboration of alkynes up to early 2017. The reaction conditions, regio- and stereoselectivities, and mechanisms are summarized in detail. Moreover, synthetic applications and perspectives on the diboration of alkynes are also discussed.