Regio‐ and Stereoselective Synthesis of Valuable Tetracyclic Compounds by Intramolecular Diels–Alder Reactions between Furan and Cyclopropene Moieties

Abstract

A direct regio‐ and diastereoselective synthetic route for valuable tetracyclic compounds that employs intramolecular Diels–Alder reactions between furanyl and electron‐deficient cyclopropene groups has been developed. The reaction readily proceeds under mild basic conditions to afford potentially bioactive ring‐fused tetracyclic compounds in moderate to high yields with high diastereoselectivities (up to > 20:1). Selective reduction reactions of the Diels–Alder adducts with a Zn/acetic acid system can provide octahydro‐1H‐cyclohepta[c]furan‐1‐ones, which can subsequently undergo acyl transfer reactions with aliphatic amines.