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

摘要

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.