Enantioselective Total Synthesis of (-)-Hamigeran F and Its Rearrangement Product.

Herein, we report the first enantioselective total synthesis of the highly complex hamigeran diterpenoid (-)-hamigeran F and its rearrangement product. The synthetic strategy features key steps of asymmetric hydrogenation, Horner-Wadsworth-Emmons olefination, and intramolecular Friedel-Crafts acylation to construct the [6,6,5]-tricyclic skeleton bearing three consecutive stereocenters, a sequence of steps involving Rosenmund reduction, Wittig reaction, dihydroxylation to assemble the α-acetoxy ketone group, and an intramolecular aldol reaction to build the tetracyclic core structure.