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 support the proposed reaction mechanism.

Automated summary

This study describes an efficient and regioselective synthesis of isoquinolones by [4 + 2]-annulation of N-chlorobenzamides with vinyl acetate in the presence of CoCp*(III) catalyst. The annulation reaction was further diversified by using vinyl ketones, leading to the preparation of biologically valuable isoquinolone derivatives in good yields. Additionally, mechanistic investigations including deuterium labeling study and competition experiment were performed to support the proposed reaction mechanism.