AN EFFICIENT SYNTHESIS OF TRIFLUOROMETHYL PYRROLES AND RELATED-COMPOUNDS FROM EASILY PREPARED TRIFLUOROMETHYLOXAZOLONES

An efficient way for the synthesis of trifluoromethylpyrroles and rela ted compounds from easily prepared trifluoromethyloxazolone via 1,3-di polarcycloaddition and the base promoted cyclocondensation reaction wa s described. The 1, 3-dipolar-cycloaddition of trifluoromethyloxazolon e and the activated carbon-carbon multiple bond gave primary cyclo-add uct 2 or 4, which were transformed into trifluoromethylpyrroles after decarboxylation. The base promoted cyclocondensation involves the tand em Michael addition of trifluoromethyloxazolones to electron-deficient alkenes, intramolecular cyclization and decarboxylation and directly gave desired trifluoromethylpyrroles in good yield.