Regioselective Synthesis of Highly Aryl‐Substituted Pyrrole Carboxylates as Useful Medicinal Chemistry Leads

The regioselective syntheses of two pharmaceutically relevant pyrrole scaffolds are described. A synthetic route for the preparation of differentially substituted pyrrole‐3,4‐dicarboxylates is presented and exemplified. This route circumvents some of the problems and limitations associated with previous butynedioic diester condensations and 1,3‐dipolar cycloaddition reactions. A route to the related 4,5‐diarylpyrrole‐2‐carboxylic acid scaffold is also presented. Both routes allow for the regiocontrolled preparation of highly substituted pyrrole pharmacophore cores.