methyl (3R,4R,4aR,6R,8R,8aR)-4-allyl-6-((tert-butoxycarbonyl)amino)-1,7-dioxooctahydro-1H-3,8-methanoisochromene-4-carboxylate

methyl (3R,4R,4aR,8R,8aR)-4-allyl-6-((tert-butoxycarbonyl)amino)-1,7-dioxo-3,4,4a,7,8,8a-hexahydro-1H-3,8-methanoisochromene-4-carboxylate

tert-butyl (R)-4-((1R,4R,5R)-7-(methoxycarbonyl)-3-oxo-2-oxabicyclo[2.2.2]oct-7-ene-5-carbonyl)-2,2-dimethyloxazolidine-3-carboxylate

tert-butyl (R)-4-((1S,4S,5S)-7-(methoxycarbonyl)-3-oxo-2-oxabicyclo[2.2.2]oct-7-ene-5-carbonyl)-2,2-dimethyloxazolidine-3-carboxylate

(2R)-2-(tert-butoxycarbonylamino)-3-oxo-3-(4-methyl)phenylpropyl acetate