Silver-Catalyzed Regioselective Synthesis of Highly Substituted 2-Trifluoromethyl Pyrroles.

An efficient and regioselective synthesis of highly substituted 2-trifluoromethyl pyrrole derivatives via silver-catalyzed cyclization of vinyl azides with ethyl 4,4,4-trifluoro-3-oxobutanoate is reported. Various α-(heteo)aryl, alkyl, β-aryl, as well as α,β-disubstituted vinyl azides, participate in this transformation. The reaction mechanism likely involves the addition of in situ generated 2H-azirine to the diketone species, followed by intramolecular addition, N-C1 cleavage, and elimination.