(-)-Cephalotaxinone

(4S,5S)-1,2-didehydro-2-methoxy-cephalotaxane-3,8-dione

6-chloro-2,2-dimethyl-3a,6a-dihydro-cyclopenta[1,3]dioxol-4-one

(+)-6-chloro-2,2-dimethyl-5-(phenylselenyl)tetrahydrocyclopenta[1,3]dioxol-4-ol