Cu-Catalyzed switchable synthesis of functionalized pyridines and pyrroles.

Herein, we describe a high yielding and switchable synthesis of a range of functionalized pyridines and pyrroles via Cu-catalyzed cascade reactions with alkynes and N-sulfonyl azadienes which are readily available from saccharin. Both unsymmetrical 2,4,6-trisubstituted pyridines and multi-substituted pyrroles could be transformed into some bioactive compounds and chiral ligands.