5-[N-(tert-butoxycarbonyl)amino]-1-(tert-butyl-dimethylsilyloxy)-2-pentene

(2R,3R)-5-[N-(tert-butoxycarbonyl)amino]-1-(tert-butyl-dimethylsilyloxy)pentan-2,3-diol

ethyl (E)-5-(tert-butoxycarbonylamino)pent-2-enoate

(1R,3aR,7aR,8R)-6,6-dimethylhexahydro-1,5,7-trioxa-3-azacyclopropa[a]naphthalene-3-carboxylic acid tert-butyl ester

(S)-6-hydroxymethyl-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester