First total synthesis of verbalactone, a macrocyclic dilactone isolated from Verbascum undulatum

Verbalactone, a new macrocyclic dilactone was synthesized efficiently in a steroselective manner involving a Barbier–Grignard reaction, a Sharpless asymmetric dihydroxylation, monotosylation, epoxidation, ring opening of the epoxide, hydrolysis and lactonization. A δ-lactone, (+)-(3R,5R)-3-hydroxy-5-decanolide was also formed along with the dimeric lactone.