C. C. Li. S. Liang, X. H. Zhang, Z. X. Xie, J. H. Chen*, Y. D.Wu*, Z. Yang*

Org. Lett. 2005, 7, 3709.

Construction of the [5-7-6] tricyclic core of guanacastepenes was attempted by using the intramolecular Diels−Alder (IMDA) reaction and Me3Al-mediated ring opening of the oxabridge as key synthetic steps. The illustrated chemistry demonstrated a synthetic feasibility to build up the framework of guanacastepenes by the IMDA reaction.