Aromatic Precursors in Trichothecene Synthesis. The Addition of Lithio Ethyl Acetate to a Pyrilium Salt

Several approaches to the synthesis of the cytotoxic trichothecene1 compounds have been reported recently2,3 including a total synthesis of trichodermin, 1, by Raphael and co-workers.4 The synthetic strategy of these efforts has been based on the serial construction of the three rings beginning with an appropriately substituted cyclohexane ring A. We have been exploring a number of pathways to these biologically interesting compounds5, one of which departs from an A/B aromatic precursor. We wish to report here the use of a benzopyrilium salt for the preparation of a potential trichothecene intermediate.