Reverse Regioselective Cp*Co(III)-Catalyzed [4+2] C−H Annulation of N-Chloroamides with Vinyl Silanes: Synthesis of 4-Silylated Isoquinolones and its Application for the Synthesis of 3,4-Dihydroisoquinolones

We have developed Cp*Co(III)-catalyzed reverse regioselective [4+2] annulation of N-chlorobenzamides/acrylamides with vinyl silanes for the synthesis of 4-silylated isoquinolones. The reaction was performed at ambient temperature under redox-neutral conditions. The reaction utilizes the N-Cl bond as an internal oxidant and furnished the required products with excellent regioselectivities and demonstrated high functional group tolerance. Moreover, 4-silylated isoquinolone derivatives were readily converted into 3,4-dihydroisoquinolones via protodesilylation thus making vinyl silane an ethylene surrogate.