Scope and mechanism of palladium-catalyzed amination of five-membered heterocyclic halides.
Detailed studies have been conducted to determine the activity of palladium catalysts for the amination of five-membered heterocyclic halides and to determine the factors that control the scope of this reaction. Palladium-catalyzed aminations of the electron-rich furanyl, thiophenyl, and indolyl halides and of the related 2-halogenated thiazoles, benzimidazole, and benzoxazole have been shown to occur with a subset of amines. Various combinations of palladium precursors and P(t)Bu(3) were tested as catalysts for reaction of 3-bromothiophene with N-methylaniline, and the fastest reactions occurred with the Pd(I) dimer, [PdBr(P(t)Bu(3))](2). The fastest aminations of thiazoles, benzimidazoles, and benzoxazoles occurred with the combination of palladium trifluoroacetate and P(t)Bu(3) as catalyst.
Hooper
Mark W
MW
Department of Chemistry, P.O. Box 208107, Yale University, New Haven, Connecticut 06520-8107, USA.
Utsunomiya
Masaru
M
Hartwig
John F
JF
D000586:Amination; D001562:Benzimidazoles / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D005663:Furans / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D007202:Indicators and Reagents; D007211:Indoles / Q000737:chemistry; D007700:Kinetics; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry
D001562:Benzimidazoles; D005663:Furans; D006846:Hydrocarbons, Halogenated; D007202:Indicators and Reagents; D007211:Indoles; D009942:Organometallic Compounds; D010080:Oxazoles; D013844:Thiazoles; D010165:Palladium