Synthesis of Trifluoromethyl Pyrroles

Significance

The regioselective synthesis of 4-amino- or 4-alkoxy-substituted 2-trifluroropyrroles under mild conditions and in moderate to good yields is reported. A number of alkoxysubstituted pyrroles were synthesized in yields which were lower than those of the amino-substituted pyrroles with N-dialkyl, N-dibenzyl, pyrrolidinyl, piperidinyl, and morpholine groups. The synthesis of the alkoxy-substituted acyclic precursors was reported earlier by the same group (A. Collar, G. Clar, M. A. P. Martins, S. Kimmer, P. Fischer Synthesis 1991, 483-486). Treatment with triphenyl­phosphine leads to the iminophosphoranes (Staudinger reaction), which then undergo an intra­molecular aza-Wittig reaction to form the pyrroles.