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

An unexpected silver-catalyzed cascade reaction of β-enaminones and isocyanoacetates affording functionalized pyrrole derivatives is reported. In this reaction, tautomeric equilibria of β-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.