An Efficient, High-Yield Preparation of Substituted 2,2′-Bipyrroles

Abstract

An improved synthesis of alkyl substituted 2,2′-bipyrroles is described. It involves first pyrrolic nitrogen protection of substituted 2-iodopyrroles, then Ullmann-type coupling, followed finally by deprotection of the resulting 2,2′-bipyrroles. Using this procedure, yields of 2,2′-bipyrroles are typically enhanced by 20 to 30% depending on the pyrrole ring substitution and the scale of the reaction.