Sodium borohydride or potassium carbonate-mediated intramolecular Michael addition: a general method for the synthesis of fused dihydrofuran and furan derivatives

A simple and convenient method for the synthesis of fused dihydrofuran derivatives using NaBH4-mediated reductive cyclization and fused furan derivatives by K2CO3-mediated intramolecular Michael addition followed by acid-catalyzed methanol elimination has been developed.