title: Palladium-nanoparticle-catalysed Ullmann reactions in ionic liquids with aldehydes as the reductants: scope and mechanism.
abstract: An efficient Ullmann-type reductive homocoupling of aryl, vinyl and heteroaryl halides can be promoted by an aldehyde in tetraalkylammonium ionic liquids under very mild reaction conditions. This simple procedure generates symmetrical biaryls under relatively mild conditions. The ionic liquid is crucial for this process because it behaves simultaneously as a base, ligand and reaction medium. The role of the aldehyde is also discussed and a general mechanism for this unusual reaction is proposed. These results open the way to a new efficient method of Pd-catalysed dehydrogenation of carbonyl compounds.
authors.affiliation: Department of Chemistry, University of Bari, Via Orabona, 4, 70126 Bari, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Calò
authors.forename: Angelo
authors.initials: A
authors.lastname: Nacci
authors.forename: Antonio
authors.initials: A
authors.lastname: Monopoli
authors.forename: Pietro
authors.initials: P
authors.lastname: Cotugno
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D006219:Halogens / Q000737:chemistry; D006841:Hydrocarbons, Aromatic / Q000138:chemical synthesis* / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D019163:Reducing Agents
chemical_list: D000447:Aldehydes; D006219:Halogens; D006841:Hydrocarbons, Aromatic; D052578:Ionic Liquids; D019163:Reducing Agents; D010165:Palladium