Asymmetric synthesis of the core structure of leucosceptroids A-D.

The asymmetric synthesis of the core structure of leucosceptroids A-D has been achieved. The key steps of the synthesis includes the formation of the cis-2,5-disubstituted THF ring by TPAP catalytic oxidative cyclization followed by a highly diastereoselective intramolecular Diels-Alder reaction to fashion the fused tricyclic hydrindane ring system.