Rapid Access to Sulfenylated Spiro[5.5]trienones via PIFA‐promoted Dearomative Spirocyclization of Biaryl Ynones

Abstract A fast and facile protocol for the sulfenylative spirocyclization of biaryl ynones employing PIFA under mild conditions is reported. A range of sulfenylated spiro[5.5]trienones were obtained in moderate to good yields. This transformation involves a radical process via a 6‐ exo ‐trig dearomative spirocyclization procedure. This method can be extended to the synthesis of selenium or tellurium‐substituted spiro[5.5]trienone.