Dealkenylative Alkynylation Using Catalytic FeII and Vitamin C

In this paper, we report the synthesis of alkyl-tethered alkynes through ozone-mediated and Fe-II-catalyzed dealkenylative alkynylation of unactivated alkenes in the presence of alkynyl sulfones. This one-pot reaction, which employs a combination of a catalytic Fe-II salt and L-ascorbic acid, proceeds under mild conditions with good efficiency, high stereoselectivity, and broad functional group compatibility. In contrast to our previous Fe-II-mediated reductive fragmentation of alpha- methoxyhydroperoxides, the Fe-II-catalyzed process was devised through a thorough kinetic analysis of the multiple competing radical (redox) pathways. We highlight the potential of this dealkenylative alkynylation through multiple post-synthetic transformations and late-stage diversifications of complex molecules, including natural products and pharmaceuticals.

Automated summary

This paper reports a new method for the synthesis of alkyl-tethered alkynes and explores its mechanism and potential applications.