A formal synthesis of (-)-cyanolide A featuring a stereoselective Mukaiyama aldol reaction and oxocarbenium reduction.

The formal synthesis of the marine natural product (-)-cyanolide A is presented. The synthetic strategy is centered on two acyclic diastereoselective reactions and a single cyclic reaction with modest to excellent dr based on an initial stereocenter. Most notable is a highly stereoselective oxocarbenium reduction based on a "mismatched" reactive conformer to afford the β-C-glycoside subunit leading to an efficient synthesis of the diolide aglycon in 12 overall steps.