Alkynes are widely used as feedstock chemicals and functional groups in organic chemistry1,2. However, although the hydrogenation from an alkyne to an alkene is well established, typical methods for the reverse reaction—conversion of an alkene to an alkyne—are based on elimination chemistry reported in the 1860s3 and use forcing conditions (strong base or high temperatures)4–6. This precludes more general application on functional molecules. Here we report a recyclable selenanthrene reagent that mediates alkenes desaturation to alkynes under mild conditions. This method shows broad compatibility with both classical leaving groups and sensitive functional groups, enabling application late-stage in the efficient synthesis of complex alkynes. Moreover, this platform enables Z/E alkenes configuration inversion or sorting that are inaccessible with existing methods, highlighting its potential for diverse downstream derivatizations.
