Total Synthesis of (-)-Glaucocalyxin A

A practically useful method for the formation of the highly oxygenated bicyclo[3.2.1]octane ring system through Mn(OAc)₃ -mediated radical cyclization of alkynyl ketones was developed, which opens up a new avenue for the total synthesis of a number of highly oxidized diterpenoids. Application of this method enabled the first total synthesis of (-)-glaucocalyxin A. Other salient features of the synthesis include a highly enantioselective conjugate addition/acylation cascade reaction, a Yamamoto aldol reaction, and an intramolecular Diels-Alder reaction to assemble the A/B ring system.