Tunable Synthesisof 4‑Acyl- and 4‑FormylPyrroles by Rhodium-Catalyzed Ring-Expansion of Azirines with Enaminones

A rhodium-catalyzed annulation of 2<i>H</i>-azirines with enaminones is presented. This protocol affords a convenient approach to the diversity-oriented synthesis of 4-acyl- and 4-formyl pyrroles with good functional group tolerance. The utility of this reaction has been demonstrated by scale-up preparation, late-stage modification of natural molecules, and synthesis of diverse derivatives.