title: An efficient [2 + 2 + 1] synthesis of 2,5-disubstituted oxazoles via gold-catalyzed intermolecular alkyne oxidation.
abstract: The first efficient intermolecular reaction of gold carbene intermediates generated via gold-catalyzed alkyne oxidation has been realized using nitriles as both the reacting partner and the reaction solvent, offering a generally efficient synthesis of 2,5-disubstituted oxazoles with broad substrate scope. The overall reaction is a [2 + 2 + 1] annulation of a terminal alkyne, a nitrile, and an oxygen atom from an oxidant. The reaction conditions are exceptionally mild, and a range of functional groups are easily tolerated. With complex and/or expensive nitriles, only 3 equiv could be sufficient to achieve serviceable yields in the absence of any solvent and using only 1 mol % BrettPhosAuNTf(2) as the catalyst.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Weimin
authors.initials: W
authors.lastname: He
authors.forename: Chaoqun
authors.initials: C
authors.lastname: Li
authors.forename: Liming
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D010080:Oxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction
chemical_list: D000480:Alkynes; D010080:Oxazoles; D006046:Gold