Cp*Co(III)-Catalyzed Regioselective Redox-Neutral Synthesis of 3-Alkenylated Isoquinolones from N-Chlorobenzamides with 1,3-Diynes at Room Temperature

We have developed Cp*Co(III)-catalyzed redox-neutral synthesis of 3-alkynylated isoquinolones via (4 + 2) annulation of N-chlorobenzamides and 1,3-diynes. The reaction displayed a broad scope and functional group tolerance and performed under mild conditions at room temperature. The high regioselectivity was observed in case of meta-substituted N-chlorobenzamides as compared to our previously developed Ru-catalytic system. The reaction is operationally simple and also applicable to the broad range of substrates with good functional group tolerance.