Regioselective and Redox-Neutral Cp*IrIII-Catalyzed Allylic C-H Alkynylation

Herein, we report a Cp*Ir-III-catalyzed highly regioselective and redox-neutral protocol for the construction of 1,4-enynes from unactivated olefins and bromoalkynes via intermolecular allylic C-H alkynylation. The developed mild reaction conditions tolerate a broad range of common functional groups, even enabling selective alkynylation of allylic C-H bonds in the presence of other prominent directing groups. Mechanistic experiments including the isolation of a catalytically active Ir-III-allyl species support an intermolecular allylic C-H activation followed by an electrophilic alkynylation.

Automated summary

This study presents a highly regioselective and redox-neutral protocol for constructing 1,4-enynes from unactivated olefins and bromoalkynes through intermolecular allylic C-H alkynylation. The developed mild reaction conditions are tolerant of a broad range of common functional groups, allowing for selective alkynylation of allylic C-H bonds in the presence of other directing groups. Mechanistic experiments support an intermolecular allylic C-H activation followed by electrophilic alkynylation.