Pd(II)-Catalyzed Tandem Cycloannulative-Alkenylation of o-Alkynyl-Phenols/Anilines with (E)-β-Iodovinyl Sulfones: A Direct Strategy To Construct 3-(Vinyl sulfonyl)benzoheterole Derivatives

Benzoheteroles and vinyl sulfones are the most promising pharmaceutical relevance motifs, yet the hybrid analogues of these scaffolds still need to be explored. We report herein a general and highly efficient Pd(OAc)2-catalyzed intramolecular cyclization and vinylation of o-alkynylphenols/o-alkynylanilines with (E)-β-iodovinyl sulfones under mild reaction conditions. A direct C(sp2)–C(sp2) cross-coupling is enabled for the diversity-oriented synthesis of vinyl sulfone-tethered benzofurans and indoles in good to high yields with excellent stereoselectivity. Notably, this tandem process was consistent at the gram scale, and in situ, generation of 2-(phenylethynyl)phenol has also been utilized in a scalable synthesis. Late-stage synthetic transformations were also further explored, including isomerization and desulfonylative-sulfenylation. Moreover, several control experiments were accomplished, and we proposed a plausible mechanism based on existing experimental results.