ChemInform Abstract: One-Step Synthesis of 2-Substituted Cyclopenta(b)benzofuran-3-ol Derivatives from 3-Substituted Coumarins

3-Ethoxycarbonylcoumarin ( 4 ) was treated with 2.4 equivalent of dimethylsulfoxonium methylide in DMF at room temperature to give a novel tricyclic product, ethyl (3 a R ∗ , 8 b S ∗ )- 3a,8b-dihydro-3-hydroxy -1H- cyclopenta [b] benzofuran-2-carboxylate ( 5 ), in 64% yield. This reaction could be applied to several 3-substituted coumarins.