Preparation of 2,5,7-trithiabicyclo[2.2.1]heptane from 1,2-bis-triisopropylsilanylsulfanyl alkenes

[reaction: see text] The chemical behavior of 1,2-bis-triisopropylsilanylsulfanyl alkenes 1 is relatively unexplored, and the weak sulfur-silicon bonds give rise to various transformations. Under acidic conditions (HCl) and in the presence of a Lewis acid at room temperature the bicyclic adduct 2 is obtained in good yield. The structure was confirmed by X-ray crystal analysis with R = benzyl.