Stereoselective Synthesis of Highly Functionalized Indanes and Dibenzocycloheptadienes through Complex Radical Cascade Reactions

Two highly stereoselective radical‐mediated syntheses of densely functionalized indanes and dibenzocycloheptadienes from ortho ‐vinyl‐ and ortho ‐vinylaryl‐substituted N ‐(arylsulfonyl)‐acrylamides, respectively, are presented here. The chemoselective addition of in situ generated radicals (X . ) onto the styrene moieties triggers an unprecedented reaction cascade, resulting in the formation of one new CX bond and two new CC bonds, a formal 1,4‐aryl migration, and the extrusion of SO 2 to generate an amidyl radical intermediate. This intermediate, upon H abstraction, leads to the observed 5‐ and 7‐membered ring carbocyclic products, respectively, in a highly efficient manner.