Cp*Co(III)-Catalyzed Regioselective [4+2]-Annulation of N-Chlorobenzamides with Vinyl Acetate/Vinyl Ketones

An efficient and straightforward strategy for the synthesis of isoquinolones through [4 + 2]-annulation of N-chlorobenzamides with vinyl acetate in the presence of CoCp*(III) catalyst in a regioselective manner is described. Furthermore, the annulation reaction was diversified by using vinyl ketones. By utilizing this strategy, biologically valuable isoquinolone derivatives were prepared in good yields. Subsequently, isoquinolone derivatives were further transformed into 1-chloroisoquinolines in the presence of POCl3. Furthermore, mechanistic investigations such as deuterium labeling study and competition experiment were performed to O O CI POCl3 N R, iota * cost effective Co catalyst * Isoquinolones * Internal oxidizing DG * ambient temperature * functional group tolerance Me support the proposed reaction mechanism.