An enantioselective synthesis of a 6oxygenated atisine derivative 20 is described. The atisine skeleton 18 was stereoselectively constructed by the intramolecular double Michael reaction of the enone ester 16. derived. through the al&hy& 3, from the symmetrical ketone 4. The diterpenoid alkaloids have long been of interest because of their pharmacological properties, complex molecular structure, and interesting chemistry.* Recently, we achieved the synthesis of atisine2 in a naturally occurring enantiomeric form via the intramolecular double Michael reaction as a key step.3 The further extension of this strategy to the synthesis of other alkaloids has fascinated us. A number of diterpenoid alkaloids possess oxygen functionalities on the ring B,t and it is considered that the oxygen group at the C-6 position would assist in the bond formation between the C-7 and the C-20. Thus a synthesis of a 6-oxygenated atisine derivative 1 was examined as a preliminary experiment intending the total synthesis of ditetpenoid alkaloids having a more complicated architecture. It was further planned that the substrate 2 of the key reaction could be prepared from the aklehyde 3, enantioselectively derivatixed from the symmetrical ketone 4 (Scheme I).3 C02Me 0 CO,Me a OMOM 4 Scheme 1 OMOM OMOM OMOM Me2VOWH2 _____ -___--MeozC.