Formal total synthesis of coriolin has been accomplished on the basis of a [3+2] cycloaddition reaction of a vinylsulfide with 3-(methylthio)-2-siloxyallyl cation. A five-membered vinylsulfine as a C ring unit was prepared in five steps from commercially available compounds. The first [3+2] cycloaddition reaction gave the BC ring intermediate, which was then converted into a bicyclic vinylsulfide in
unit (S)-7 gave bicyclic ketones 8 and 9, which were easily converted into vinyl sulfide 11. Stereoselective construction of the A-ring was achieved by the second [3+2] cycloaddition reaction of the BC-ring unit. New methods for introduction of the oxygen functional groups to the triquinane skeleton were also developed for the last stages of the total synthesis. Thus, the C7 hydroxyl group was introduced