Protecting-Group-Free Synthesis of Taiwaniaquinone H Using a One-Pot Thermal Ring Expansion/4π-Electrocyclization Strategy

A strategy to the 6-5-6 tricyclic scaffold of taiwaniaquinoids was established on the basis of a one-pot thermal ring expansion/4 pi-electrocyclization process. The efficiency of this methodology has been demonstrated through its application in the total synthesis of taiwaniaquinone H, which has been accomplished in three steps and 14% overall yield in a protecting-group-free manner starting from commercially available materials.