Cobalt-Catalyzed Hydroalkynylation of Vinylaziridines

Transition metal-catalyzed hydroalkynylation reactions are efficient transformations allowing the straightforward formation of functionalized alkynes. Therein, we disclose the cobalt-catalyzed hydroalkynylation of vinylaziridines giving rise to both linear and branched enynes. The optimization of the reaction conditions allowed to determine the key parameters of the cobalt-based catalytic system. The scope investigation showed that the cobalt-catalyzed hydroalkynylation is mainly limited to phenylacetylene derivatives. In most cases branched and linear enynes were isolated in equimolar proportions (20 examples). Additional experiments allowed us to propose a plausible mechanism. Finally, the hydroalkynylation products were further subjected to an iodocyclization affording a 2,3-dihydropyrrole derivative and a platinum-catalyzed cycloisomerization.

Automated summary

A novel cobalt-catalyzed hydroalkynylation reaction was discovered, enabling the synthesis of enynes from vinylaziridines. The study showed that the cobalt-catalyzed hydroalkynylation reaction is mainly applicable to phenylacetylene derivatives, with branched and linear enynes formed in equimolar proportions in most cases.