title: Nickel-catalyzed cross-coupling of chromene acetals and boronic acids.
abstract: A modular and highly efficient protocol for the synthesis of 2-aryl- and heteroaryl-2H-chromenes is described. Under base-free conditions, readily accessible 2-ethoxy-2H-chromenes undergo C(sp(3))-O activation and C(sp(3))-C bond formation in the presence of an inexpensive nickel catalyst and boronic acids. This new strategy enables broad access to 2-substituted-2H-chromenes and has been applied to the late-stage incorporation of complex molecules, including the pharmaceuticals loratidine and indomethacin methyl ester.
authors.affiliation: Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
authors.forename: Thomas J A
authors.initials: TJ
authors.lastname: Graham
authors.forename: Abigail G
authors.initials: AG
authors.lastname: Doyle
mesh_terms: D000080:Acetals / Q000737:chemistry*; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*
chemical_list: D000080:Acetals; D001578:Benzopyrans; D001897:Boronic Acids; D009532:Nickel