Practical Synthesis of Pharmaceutically Relevant Pyrroles from α,β‐Unsaturated Aldehydes and Phenacyl Azides

Structurally diverse pyrroles were synthesized via direct coupling of α, β-unsaturated aldehydes and phenacyl azides at ambient temperature without using any strong base or transition metal catalyst. The reaction offers great compatibility in product formation with readily available starting materials and non-requirement of specialized reaction conditions (very high or extremely low cryogenic temperature, anhydrous solvents, inert atmosphere, etc.) thereby minimizing the laborious practice of synthesizing pyrroles. The scope of the synthetic method was successfully demonstrated by synthesizing 28 different phenyl(5-phenyl-1H-pyrrol-2-yl)methanones in high yields (87-95%). Derivatization of a few synthesized pyrroles was demonstrated which shows the potential application of the developed protocol in new functional materials. To get a mechanistic insight of the reaction, a typical reaction was performed in a deuterated solvent and the progress of the reaction was monitored by recording its 1H NMR at regular time intervals.