Synthesis of beta,betaʹ-linked bispyrrolyl chalcones

Pyrroles are important building blocks in natural products and medicinal chemistry; they can be linked together in various ways to make a multitude of functional oligomers and macrocycles. One simple way in which pyrroles have not previously been linked together, is through the beta-positions of two pyrroles to make a chalcone. To address this knowledge gap, we report herein an efficient method for synthesising beta,betaʹ-linked bispyrrolyl chalcones, proceeding via a Knoevenagel-type reaction of a pyrrolyl aldehyde, followed by a late-stage Friedel-Crafts reaction to attach the second pyrrole. We envisage that the obtained structures may be elaborated in the future within medicinal chemistry programs.