Silver-Catalyzed Cascade Reaction of β-Enaminones and Isocyanoacetates To Construct Functionalized Pyrroles

An unexpected silver-catalyzed cascade reaction of beta-enaminones and isocyanoacetates affording functionalized pyrrole derivatives is reported. In this reaction, tautomeric equilibria of beta-enaminones are utilized to generate imine partners in situ. A hypothesized sequential Mannich addition/ cyclization of imine tautomers and isocyanoacetates followed by an unprecedented ring-opening of the resultant 2-imidazolines and dehydration condensation deliver the final 1,2,4,5-tetrasubstituted pyrrole products.