title: Practical, modular, and general synthesis of benzofurans through extended Pummerer annulation/cross-coupling strategy.
abstract: Operationally simple, efficient, and widely applicable Pummerer annulations of simple phenols with ketene dithioacetal monoxides, with the aid of trifluoroacetic anhydride, have been shown to provide a variety of benzofurans having a methylthio group at the 2-position. Subsequent and newly developed nickel-catalyzed arylation at the methylthio group culminates in diversity-oriented synthesis of multisubstituted benzofurans. Our extended Pummerer annulation/cross-coupling sequence is powerful enough to synthesize biologically active natural products as well as highly fluorescent benzofuran derivatives.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); The Hakubi Center for Advanced Research, Kyoto University (Japan).
authors.forename: Kei
authors.initials: K
authors.lastname: Murakami
authors.forename: Hideki
authors.initials: H
authors.lastname: Yorimitsu
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Osuka
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis
chemical_list: D001572:Benzofurans
keywords: annulation; heterocycles; nickel; rearrangement; synthetic methods