A general method for the preparation of 5-trifluoromethylated oxazoles from α-amino acids
The reactions of N-acyl-N-benzyl-α-amino acids (1) or N-acylprolines (5) with trifluoroacetic anhydride in the presence of pyridine afford 5- trifluoromethyloxazoles (2 or 7) in good yields. The reaction could proceed through the transient formation of me
Kawase, Masami,Miyamae, Hiroshi,Kurihara, Teruo
p. 749 - 756
(2007/10/03)
Unexpected Product from the Dakin-West Reaction of N-Acylprolines using Trifluoroacetic Anhydride: A Novel Access to 5-Trifluoromethyloxazoles
The base-catalyzed reaction of N-acylprolines with trifluoroacetic anhydride proceeds through mesoionic 1,3-oxazolium-5-olates followed by the pyrrolidine ring cleavage to afford the 5-trifluoromethyloxazoles in good yields.Key Words: N-acylproline; oxazo