Weinreb Amide Directed Versatile C−H Bond Functionalization under (η5‐Pentamethylcyclopentadienyl)cobalt(III) Catalysis

The (η5‐pentamethylcyclopentadienyl)cobalt(III) (Cp*CoIII)‐catalyzed C−H bond functionalization of aromatic, heteroaromatic, and α,β‐unsaturated Weinreb amides was explored. C−H allylation reactions with the use of allyl carbonate and a perfluoroalkene, oxidative alkenylation reactions with the use of ethyl acrylate, iodination reactions with the use of N‐iodosuccinimide, and amidation reactions with the use of dioxazolones were catalyzed by Cp*Co(CO)I2 in the presence of a cationic Ag salt and AgOAc to afford various synthetically useful building blocks. Mechanistic studies of the C−H allylation disclosed that the C−H activation step was rate determining and virtually irreversible. Amides & Co: Various Weinreb amide directed C−H bond functionalization reactions proceed under (η5‐pentamethylcyclopentadienyl)cobalt(III) (Cp*CoIII) catalysis. The C−H allylation, alkenylation, iodination, and amidation reactions of aromatic and α,β‐unsaturated Weinreb amides provide synthetically useful building blocks by using a readily available first‐row transition‐metal catalyst. FG=functional group.