Direct conversion from alkenes to alkynes.

Meng, Junhong; Liang, Yiqi; Xu, Ruilin; Cheng, Zengrui; Huang, Yilei; Shi, Hongwei; Chen, Yichi; Wang, Xi et al. · Nature · 2026

basic_science · Level V

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Abstract

Alkynes are widely used as feedstock chemicals and functional groups in organic chemistry<sup>1,2</sup>. 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 1860s<sup>3</sup> and use forcing conditions (strong base or high temperatures)<sup>4-6</sup>. 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.