Domino Reaction for the Synthesis of Polysubstituted Pyrroles and Lamellarin R.

A three-component annulation reaction was developed for the synthesis of pyrroles, a class of compounds with various properties valuable to biomedical and polymer industries. Treatment of a-silylaryl triflates, Schiff bases, and alkynes generated polysubstituted pyrroles in good yields (61-86%) with regioselectivity. This domino reaction involved completion of five sequential steps in a single flask, which comprised aryne formation through 1,2-elimination, their alkylation by Schiff bases through 1,2-addition, 1,4-intramolecular proton transfer, Huisgen 1,3-dipolar cycloaddition, and dehydrogenative aromatization. It was then successfully applied as the key step in the synthesis of the natural product lamellarin R. This new reaction represents an efficient, sustainable process for the production of chemical materials.