A general domino annulation reaction of sulfonylmethyl
isocyanide
with trifluoroacetic anhydride in the presence of copper chloride
as an additive is developed. The reaction affords 2,5-bis(trifluoromethyl)oxazoles
in modest to good yields under mild conditions. A wide variety of
sulfonylmethyl isocyanide and perfluorocarboxylic anhydride substrates
are amenable to this transformation. Under a higher copper salt loading
conditions, the reaction led to the formation of monotrifluoromethyl-substituted
oxazole product.