Synthesis of Methyl 3-Aryl-4-trifluoromethyl-1<i>H</i>-pyrrole-2-carboxylates

Abstract

Thermal addition of methyl 1-tert-butylaziridine-2-carboxylate (1) to 1-aryl-3,3,3-trifluoro-1-propynes 3 followed by dehydrogenation of intermediate pyrrolines 4,5 afforded isomeric methyl 1-tert-butyl-3(4)-aryl-4(3)-trifluoromethyl-1H-pyrrole-2-carboxylates 7 and 8 in high yields. Dealkylation of some 3-aryl derivatives, e. g. 7b,c with trifluoromethanesulfonic acid, gave methyl 3-aryl-4-trifluoromethyl-1H-pyrrole-2-carboxylates 9b,c.