Radical Borylative Cyclization of 1,6-Dienes: Synthesis of Boron-Substituted Six-Membered Heterocycles and Carbocycles

A radical borylative cyclization reaction of 1,6-dienes was developed to assemble boron-handled six membered heterocycles and carbocycles. This reaction was initiated by the chemo- and regio-controlled addition of an N-heterocyclic carbene boryl radical to one of the alkene tethers, followed by an intramolecular 6-exo cyclization to afford a six membered ring framework. The utility of this method was demonstrated in the synthesis of diverse paroxetine analogues through late-stage derivatization of the boryl functional unit.