(5S,1'R)-4,5-dihydro-5-(1'-mesyloxy)ethyl-2-(3H)-furanone

ethyl (2S,3S)-3-hydroxy-2-methyl-1,8,9-triazabicyclo<3.4.0>non-8-ene-7-carboxylate

ethyl (2S,3S)-6-(3-tert.-butyldimethylsilyloxy-2-methyl)piperidylidene carboxylate

(5S,6R)-5,6-O-isopropylidene-azepane-2-one

6-azido-5-tert-butyldimethylsilyloxy-2,3,6-trideoxy-D-erythro-hexono-1,4-lactone