Rapid assembly of the bicyclo[5.3.1]undecenone core of penostatin F: a successive Diels-Alder/Claisen reaction strategy with an efficient stereochemical relay.

The first synthesis of the tricyclic core of Penostatin F (1) using a stereocontrolled Diels-Alder reaction and a Claisen rearrangement in succession has been achieved in nine steps from commercially available methyl acetoacetate and (E)-2-decenal. Penostatin F is a metabolite isolated from a fungal strain of Penicillium sp., OUPS-79, separated from the marine alga Enteromorphia intestinalis and exhibits significant cytotoxicity against cultured P388 Leukemia cells (ED(50) = 1.4 micromol/mL). [reaction: see text]