Studies directed towards the total synthesis of botcinic acid, the revised structure of botcinolide: synthesis of the highly substituted tetrahydropyran moiety

Synthesis of the highly substituted polyoxygenated tetrahydropyran ring of botcinic acid, the revised structure of botcinolide is achieved using, as key steps, a highly stereoselective aldol reaction of the titanium enolate from a lactate-derived chiral ketone and a stereoselective dihydroxylation.