Synthesis of Naphthofurans by tBuOK‐Catalyzed Intramolecular Anionic Cycloaddition of Unsymmetrical Bis‐propargyl Ethers

Abstract

The tBuOK-catalyzed intramolecular anionic cycloaddition of unsymmetrical bis-propargyl ethers has been applied to the synthesis of naphthofurans. A systematic study of the cyclization system revealed that the amount of base and solvent played an essential role in this reaction. The results showed that the cyclization preceded cleanly and smoothly under mild reaction conditions, employing a catalytic amount of tBuOK as base, THF as solvent, at room temperature in a short reaction time (15 min). The reaction was regioselective,