Thiochromane Formation via Visible-Light-Mediated Intramolecular ?-C(sp3)-H Bond Arylation of Sulfonamides

Visible-light-mediated intramolecular site-selective delta-C(sp3)-H bond arylation of aliphatic trifluoromethanesulfona-mides was developed. The reaction proceeds through a radical cascade, including the generation of a sulfonamidyl radical, which triggers a 1,5-hydrogen atom transfer, affording a delta-C-centered radical, which finally cyclized onto a neighboring thiopolyfluoroaryl moiety to deliver a range of synthetically useful thiochromanes. The cyclization process occurs through two distinct pathways depending upon the nature of the substituent X ortho to the native C-S bond.