title: C-2 selective arylation of indoles with heterogeneous nanopalladium and diaryliodonium salts.
abstract: A simple and efficient method to prepare synthetically useful 2-arylindoles is presented, using a heterogeneous Pd catalyst and diaryliodonium salts in water under mild conditions. A remarkably low leaching of metal catalyst was observed under the applied conditions. The developed protocol is highly C-2 selective and tolerates structural variations both in the indole and in the diaryliodonium salt. Arylations of both N-H indoles and N-protected indoles with ortho-substituted, electron-rich, electron-deficient, or halogenated diaryliodonium salts were achieved to give the desired products in high to excellent isolated yields within 6 to 15 h at room temperature or 40 °C.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm (Sweden), Fax: (+46) 8-154908.
authors.forename: Joel
authors.initials: J
authors.lastname: Malmgren
authors.forename: Anuja
authors.initials: A
authors.lastname: Nagendiran
authors.forename: Cheuk-Wai
authors.initials: CW
authors.lastname: Tai
authors.forename: Jan-E
authors.initials: JE
authors.lastname: Bäckvall
authors.forename: Berit
authors.initials: B
authors.lastname: Olofsson
mesh_terms: D002384:Catalysis; D006841:Hydrocarbons, Aromatic / Q000138:chemical synthesis* / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D007455:Iodine / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D010165:Palladium / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*
chemical_list: D006841:Hydrocarbons, Aromatic; D007211:Indoles; D012492:Salts; D010165:Palladium; D007455:Iodine
keywords: arylation; hypervalent iodine; indoles; nanopalladium; palladium catalysis