Cycloaddition Enables Ring Opening of N -Propargyl Oxazolidines: Access to N -Benzyl-2,3-diphenylpyrroles via Both C–O and C–C Bond Cleavage

Abstract

Aza-diarylmethanes represent a privileged class of pharmacophores found in numerous bioactive molecules. However, conventional synthetic approaches often suffer from the need for prefunctionalized starting materials, harsh reaction conditions, and limited substrate compatibility. We herein develop a metal- and oxidant-free tandem cyclization/ring-opening strategy for the synthesis of N-benzyl-2,3-diphenylpyrroles from easily accessible 4,5-diphenyloxazolidines. Mechanistic studies reveal that DMSO serves as the primary proton source, and that benzaldehyde elimination proceeds through sequential cleavage of C–O and C–C bonds. This step-economical protocol features broad functional group tolerance, addresses the existing synthetic gap in accessing 2,3-disubstituted N-benzylpyrroles, and offers a practical route to drug-relevant pyrrole-containing aza-diarylmethanes.