(3aS,5S,6S,6aS)-6-bromo-2-oxo-hexahydrocyclopentaoxazole-5-carboxylic acid methyl ester

(1R,4S)-(+)-4-氨基环戊-2-烯甲酸

2-氮杂双环[2.2.1]庚-5-烯-3-酮