Stereoselective approaches to the total synthesis of (6R,4'S,6'R)-cryptofolione

Total syntheses of cryptofolione were accomplished by two different routes via a common intermediate that underwent a cross-metathesis (CM) reaction with a vinyl lactone. The intermediate was prepared by coupling of an acyl anion equivalent with a chiral allyl epoxide synthon, or by Prins cyclization of a trans-cinnamaldehyde with a chiral homoallylic alcohol. Goniothalamin was obtained as a cross-metathesis product of the diacetate and vinyl lactone