title: Regioselective formation of 2,5-disubstituted oxazoles via copper(I)-catalyzed cycloaddition of acyl azides and 1-alkynes.
abstract: The reaction of 1-alkynes with acyl azides in the presence of [Tpm(*,Br)Cu(NCMe)]BF(4) [Tpm(*,Br) = tris(3,5-dimethyl-4-bromopyrazolyl)methane] as the catalyst provides 2,5-oxazoles in moderate to high yields. This is a novel transformation of the CuAAC type that constitutes a significant variation of the commonly observed [3 + 2] cycloaddition reaction to yield 1,2,3-triazoles.
authors.affiliation: Laboratorio de Catálisis Homogénea, Departamento de Química y Ciencias de los Materiales, Unidad Asociada al CSIC, Centro de Investigación en Química Sostenible (CIQSO), Campus de El Carmen s/n, Universidad de Huelva, 21007-Huelva, Spain.
authors.forename: Israel
authors.initials: I
authors.lastname: Cano
authors.forename: Eleuterio
authors.initials: E
authors.lastname: Álvarez
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Nicasio
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Pérez
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010080:Oxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D001386:Azides; D009942:Organometallic Compounds; D010080:Oxazoles; D003300:Copper