macrosphelide I, has been achieved starting from commercially available chiral materials, ethyl ( S )-lactate and methyl ( R )-3-hydroxybutyrate. Titanium(IV) promoted the regioselective nucleophilic opening reaction of epoxy alcohol with benzoicacid, Sharpless epoxidation, ring-closing metathesis and Yamaguchi esterification as key steps for the construction of the 16-membered macrotriolide.