A Photoredox-Induced Stereoselective Dearomative Radical (4+2)-Cyclization/1,4-Addition Cascade for the Synthesis of Highly Functionalized Hexahydro-1H-carbazoles.

A stereoselective synthesis of functionalized hexahydrocarbazoles was developed based on an unprecedented photoredox-induced dearomative radical (4+2)-cyclization/1,4-addition cascade between 3-(2-iodoethyl)indoles and acceptor-substituted alkenes. The title reaction simultaneously generates three C-C bonds and one C-H bond, along with three contiguous stereogenic centers. The hexahydro-1H-carbazole products are highly valuable intermediates for the synthesis of novel antibiotics, as well as unnatural ring homologues of polycyclic indoline alkaloids.