Direct Multicomponent Synthesis of C3-Arylated Pyrroles under Catalyst-Free Conditions

An operationally simple catalyst-free protocol for the direct regiospecific synthesis of C3-arylated/alkenylated pyrroles has been developed. The enamine-intermediate, in situ generated from succinaldehyde and a primary amine, was trapped with activated carbonyls before the Paal–Knorr reaction in a direct multicomponent ‘just-mix’ protocol to furnish pyrroles in good yields. Several C3-substituted N-alkylpyrroles have been prepared under open-flask conditions, avoiding protection-deprotection chemistry.