Efficient Access to 3, 4‐Diarylpyrroles through Selective Bromination and Subsequent Suzuki‐Coupling Reaction

Abstract

An efficient and practical synthesis of 3, 4-disubstituted pyrrole was developed through bromination and the subsequent Suzuki-coupling reaction. The bromination of pyrrole-1-dimethylsulfonamide occurred selectively on the two β-positions to afford 3, 4-dibromo-N, N-dimethyl-1H-pyrrole-1-sulfonamide, from which symmetrical and unsymmetrical 3, 4-diarylpyrroles were prepared through a stepwise Suzuki-coupling reaction.This reaction is complementary to the existing methods and is well-tolerable by a variety of functional groups. The bromination can readily be scaled-up to gram-scale synthesis without decreasing the yield. In addition, the other halogenations of pyrrole were also studied, and different chloroproducts were isolated.