for the following products
4-[[(1,1-Dimethylethoxy)carbonyl]amino]-2-cyclopentene-1-carboxylic acid methyl ester | Methyl (1S,4R)-4-{[(tert-butoxy)carbonyl]amino}cyclopent-2-ene-1-carboxylate | Peramivir intermediate 4 and (1S,4R)-Methyl 4-(tert-butoxycarbonyl)cyclopent-2-enecarboxylate
