Stereoselective synthesis of (S,S)-palythazine from d-mannitol

Exploiting the symmetry element, an asymmetric synthesis of (S,S)-palythazine was accomplished with (R)-glyceraldehyde acetonide as the chiral precursor. The prominent steps involved stereoselective Barbier allylation, ring-closing metathesis, regioselective nucleophilic opening of epoxide, and auto-condensation of aminoketone moiety.