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 POCl 3 . Furthermore, mechanistic investigations such as deuterium labeling study and competition experiment were performed to support the proposed reaction mechanism.