Co(III)-Catalyzed Regioselective Functionalization of Isoquinolones with Naphthoquinones

A strategy for Co(III)-catalyzed C(sp2)–H alkenylation of N-protected isoquinolones with 1,4-naphthoquinones has been disclosed. The developed protocol was efficiently applied for diversely substituted isoquinolones. Preliminary mechanistic experiments revealed the involvement of a five-membered cobaltacycle as an intermediate. Deuterium labeling experiments suggested the reversible nature of the C–H activation step. The scale-up reaction was also carried out, and the product was utilized as a chemosensor to detect Fe3+ ions.