posted on 2010-11-05, 00:00authored byRyosuke Saijo, Yuri Hagimoto, Masami Kawase
Mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1), obtained from the reaction of N-acyl-N-alkylglycines with trifluoroacetic anhydride, react with phosphorus ylides to give β-trifluoromethylpyrroles (2) in good yields. The novel ring transformations of 1 into 2 occur via an initial attack of the ylide anions on the C-2 position of the ring.