Synthesis of C3,C4-Disubstituted Indoles via the Palladium/Norbornene-Catalyzed ortho-Amination/ipso-Heck Cyclization

Herein, we report the synthesis of C3,C4-disubstituted indoles via the palladium/norbornene cooperative catalysis. Utilizing N-benzoyloxy allylamines as the coupling partner, a cascade process involving ortho-amination and ipso-Heck cyclization takes place with ortho-substituted aryl iodides to afford diverse indole products. The reaction exhibits good functional group tolerance, in addition to tolerating a removable protecting group on the indole nitrogen. Divergent reactivity has been observed using the allylamine coupling partner containing more substituted olefins. Construction of the core framework of mitomycin has also been attempted with this strategy.