John Hartwig and co-workers at the University of Illinois have published in JACS on the total synthesis of taiwaniaquinone – the five membered ring was formed from a Friedel-Crafts reaction mediated by a Lewis acid (BF3 etherate). The Corey-Chaykovsky epoxidation was interesting because they state that the ylide formed from the sulfoxonium reagent did not work but the sulfonium reagent worked.
