Efficient synthesis of new 11-thiasteroids and their oxides and dioxides

We show that our strategy, involving the use of an intramolecular Diels–Alder cycloaddition of o-xylylenes as the key step, can be applied efficiently to sulphur molecules. The synthesis of sulfoxide and sulfone derivatives is described and the vinyl group of those latters is oxidized, using the Wacker process, in good yields. Moreover, X-ray crystal structures of thiasteroids and matching the trans-anti-trans ring configuration of natural products are reported.