Selective synthesis of functionalized pyrroles from 3-aza-1,5-enynes

Abstract

2-Trifluoromethyl-5-(arylsulfonyl)methyl pyrroles and 2-trifluoromethyl-4-(arylsulfonyl)methyl pyrroles were selectively synthesized from trifluoromethyl-substituted 3-aza-1,5-enynes via a cyclization/sulfonyl group migration cascade catalyzed by AgOOCCF₃ and CsOPiv, respectively. Alkylvinyl-substituted pyrroles were generated from seven-atom skeleton 3-aza-1,5-enynes via aryl sulfinic acid elimination in the presence of Cs₂CO₃. Two ion-pair intermediates were proposed and a key intermediate, aza-diene–yne, was successfully isolated in the mechanistic studies.