Iron-Mediated Segment Coupling of Alkenols with Acceptors via C-C Radical Translocation and Remote Oxidative 1,5/6-Hydrogen Atom Transfer.

Iron-mediated segment coupling followed by oxidative 1,5/6-hydrogen atom transfer (HAT) for synthesis of ε-oxo alkene derivatives is developed. This transformation involved translocation of the radical from H-to-C-to-C-to-C followed by the oxidation under MHAT conditions providing rapid access to 1,6/1,7-keto functionalized esters/ketone/sulfones/phosphonates/arenes. The different outcomes of coupling with acceptors could be explained by bond dissociation energies (BDEs), and mechanistic insights were gained through control experiments, including deuterium labeling studies.

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-- radical cyclization where indoles and pyrroles are used as an acceptor. This radical approach has also been extended for the synthesis of tetrahydrocyclopenta[]indolones via the Baldwin-disfavored 5-- 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.