From propargylic amides to functionalized oxazoles: domino gold catalysis/oxidation by dioxygen.
A new, highly efficient, and atom-economic access to a series of functionalized 2,5-disubstituted oxazoles from propargylic amides is reported. A series of propargylic amides were transformed to the corresponding alkylideneoxazolines by a gold(I) catalyst. The next step was an autoxidation to hydroperoxides bearing the heteroaromatic oxazoles. Experiments addressing the reaction mechanism reveal a radical pathway for this autoxidation process. The hydroperoxides could conveniently be converted to the corresponding alcohols by reduction with sodium borohydride.
Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany. hashmi@hashmi.de
A Stephen K
AS
Hashmi
Maria Camila
MC
Blanco Jaimes
Andreas M
AM
Schuster
Frank
F
Rominger
D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D010080:Oxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*
D000577:Amides; D010080:Oxazoles; D006046:Gold; D010100:Oxygen