7-acetoxy-1,2-didehydro-1-(ethoxycarbonyl)pyrrolizidine

seco acid

(2S,3S)-2,3-epoxy-2-methyl-6-hepten-1-ol

2(Z)-ethylidene-5-(methoxycarbonyl)-4,5-dimethyl-5-pentanolide

(4R,5R)-5-Carbomethoxy-4,5-dimethyl-2(E)-ethylidene-5-pentanolide