Multifunctionalized 3-Hydroxypyrroles in a Three-Step, One-Pot Cascade Process from Methyl 3-TBSO-2-diazo-3-butenoate and Nitrones

The synthesis of N-aryl-2-carboxyl-3-hydroxy-5-arylpyrroles has been achieved in high yield by the combination of a TBSO-substituted vinyldiazoacetate and nitrones in a one-pot cascade process involving copper-catalyzed Mannich addition, dirhodium-catalyzed dinitrogen extrusion and N-OTBS insertion, and acid-promoted aromatization (elimination).