Stereoselective total synthesis of (±)-homochelidonine

(±)-Homochelidonine, a B/C-cis-11-hydroxyhexahydrobenzo[c]phenanthridine alkaloid, was stereoselectively synthesized from arnottin II, a non-alkaloidal spirolactonyl tetralone which had been structurally correlated to chelerythrine, a fully aromatized-type alkaloid, by the common use of a 2-benzofuranyl-1-tetralone as a synthetic key intermediate. Thus, a valuable synthetic method accessible to benzo[c]phenanthridine alkaloids with different oxidation stages of the basic skeleton could be proposed.