Yz. Bi et Jm. Cook, GENERAL-APPROACH FOR THE SYNTHESIS OF MACROLINE SARPAGINE ALKALOIDS -THE TOTAL SYNTHESIS OF (+)-MACROLINE/, Tetrahedron letters, 34(28), 1993, pp. 4501-4504
(+)-Macroline 1 and a more stable equivalent 2 were synthesized from t
he tetracyclic ketone 5. The key steps in the synthesis involved a ste
reoselective Claisen rearrangement followed by hydroboration-oxidation
of the resulting olefin 14 to set the correct stereochemistry at C-15
and C-16.