cyclohexyl 2-(((1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene)amino)pent-4-enoate

cyclohexyl 2-(((1S,2S,5S)-2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-3-ylidene)amino)pent-4-enoate

(1S,2R,5S)-2-isopropyl-5-methylcyclohexyl 2-((Z)-((1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene)amino)pent-4-enoate

(1R,2S,5R)-2-isopropyl-5-methylcyclohexyl 2-(((1S,2S,5S)-2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-3-ylidene)amino)pent-4-enoate

(1R,2S,5R)-5-methyl-2-(1-methyl-1-phenylethyl)cyclohexyl (2S)-2-[(tert-butoxycarbonyl)amino]pent-4-enoate