Total Synthesis of (±)-Marsupellins A and B via Acetoxymarsupellone Using an Intramolecular Reductive Cyclization of Epoxycyanohydrin Derivative with CpTiI.

The first total synthesis of C3- and C9-oxidized -longipinane-type sesquiterpenoids containing acetoxymarsupellone, marsupellins A and B, has been accomplished. This unique core common to C3- and C9-oxidized -longipinane-type sesquiterpenoids was constructed via a new intramolecular reductive cyclization reaction of an epoxycyanohydrin derivative using CpTiI.