Rhodium(III)‐Catalyzed [4+1] Oxidative Annulation of Amides with 1,3‐enynes Through 1,4‐Rhodium Migration

Abstract Rh(III)‐catalyzed cascade oxidative C−H functionalization/aza‐annulation of indole and pyrrole‐N‐carboxamides with 1,3‐enynes involving 1,4‐rhodium migration is disclosed. This [4+1] annulation protocol provides an approach for the synthesis of imidazo[1,5‐a]indol‐3(2H)‐ones from easily accessible substrates. Moreover, sulfonamides are also found to be well compatible in this method, leading to the corresponding benzo[d]sultams. The efficacy of this protocol is highlighted by handy downstream conversions of the dienyl‐sultam.