The use of sulfur ylides in the synthesis of 3-alkyl(aryl)thio-4-trifluoromethylpyrroles from mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates

In this report, we describe a new method for the synthesis of densely functionalized pyrroles. Reaction of mesoionic 1,3-oxazolium-5-olates with various S-ylides proceeds via nucleophilic addition followed by opening of the oxazole ring and subsequent cyclization to multisubstituted pyrroles bearing both a trifluoromethyl and alkyl(aryl)thio group at 3- and 4-positions.