First total synthesis of (±)-AM6898A and (±)-AM6898D

We have established an effective method for the syntheses of (±)-AM6898D and its possible three diastereoisomers via Claisen rearrangement, stereoselective epimerization, and introduction of one isoprene unit by umpolung. Additionally, we have achieved the total synthesis of (±)-AM6898A from the same intermediate, by intramolecular aldol condensation.