Iron-Mediated Hydrogen Atom Transfer Radical Cyclization of Alkenyl Indoles and Pyrroles Gives Their Fused Derivatives: Total Synthesis of Bruceolline E and H.

The iron-mediated hydrogen atom transfer (HAT) reaction is efficaciously employed for the synthesis of dihydropyrroloindoles and dihydropyrrolizines via 5- exo - trig radical cyclization where indoles and pyrroles are used as an acceptor. This radical approach has also been extended for the synthesis of tetrahydrocyclopenta[ b ]indolones via the Baldwin-disfavored 5- endo - trig cyclization pathway. The formal synthesis of bruceolline J and the total synthesis of bruceollines E and H have been expeditiously carried out by employing the former strategy.