Redox-Neutral Radical Annulation of Challenging Alkynes with Aryl Sulfoxonium Ylides for 1-Naphthol Synthesis

This radical strategy represents the first use of sulfoxonium ylide-derived radicals in 1-naphthol synthesis and overcomes the substrate limitations of classical carbene-based methods. It enables annulation of unactivated terminal alkynes─previously challenging substrates─under mild, metal- and additive-free, visible-light conditions. Mechanistic studies support formation of a highly electrophilic hindered radical cation that undergoes polarity-inverted addition and benzannulation, establishing sulfoxonium ylides as versatile radical precursors for modular 1-naphthol construction.