Photoredox Catalytic Pentafluorosulfanylative Domino Cyclization of α‐Substituted Alkenes to Oxaheterocycles by Using SF₆

Abstract

Abstract Virtually inert sulfur hexafluoride becomes a precious pentafluorosulfanylation agent, if properly activated by photoredox catalysis, to access α‐fluoro and α‐alkoxy SF 5 ‐compounds. This advanced protocol converts SF 6 in the presence of alkynols as bifunctional C−C‐ and C−O‐bond forming reagents directly into pentafluorosulfanylated oxygen‐containing heterocycles in a single step from α‐substituted alkenes. The proposed mechanism is supported by theoretical calculations and gives insights not only in the pentafluorosulfanylation step but also into formation of the carbon‐carbon bond and is in full agreement with Baldwin's cyclization rules. The key step is a radical type 5‐, 6‐ respectively 7‐exo‐dig‐cyclization. The synthesized oxaheterocycles cannot be simply prepared by other synthetic methods, show a high level of structural complexity and significantly expand the scope of pentafluorosulfanylated building blocks valuable for medicinal and material chemistry.