A general and efficient procedure for C-H alkenylation of arenes with a broad substrate scope catalyzed by Cp*Co was demonstrated with alkynes. A highly selective mono-alkenylation and sequential bis-C-H bond functionalization was displayed to exemplify the versatility of the cobalt catalyst. Isolation of cationic Cp*Co -alkenyl intermediate was achieved under identical catalytic conditions to further establish the proposed pathway.
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