Total Synthesis of VM55599. Utilization of an Intramolecular Diels−Alder Cycloaddition of Potential Biogenetic Relevance

The total synthesis of VM55599, a natural metabolite of Penicillium sp. IMI332995, has been achieved via an intramolecular Diels−Alder cycloaddition of a reverse isoprene moiety across an azadiene system. The diastereoselectivity of the intramolecular Diels−Alder cycloaddition has biogenetic implications and is discussed in the context of the biogenetic relationship of VM55599 to the paraherquamides.