On the choice of Lewis acids for the Prins reaction; two total syntheses of (±)-Civet

While developing new variations of the Prins cyclisation reaction, the effect of the choice of Lewis acid on the outcome of the reaction and the product(s) has been investigated, yielding hitherto unseen dihydropyran products in the Prins cyclisation reaction of homoallylic alcohols, and two new modifications of the reaction: the triflate-trapped Prins adduct and the Mukaiyama–Aldol–silyl-Prins reaction. Two of these methods are employed in two complementary total syntheses of the important perfumery compound, (±)-Civet.