(5Z,7R,8R,9S,10S)-7,9:8,10-di-O-isopropylidene-7,8,9,10-tetraoxotridec-5-enoic acid tert-butyl ester

(2R,3R,4S,5R)-1-hydroxy-2,3:4,5-di-O-isopropylidene-1-O-trityl-2,3,4,5-tetraoxooctane

5-(1-phenyl-1H-tetrazol-5-ylsulfanyl)valeric acid tert-butyl ester

5-(1-phenyl-1H-tetrazole-5-sulfonyl)valeric acid tert-butyl ester

(2R,3R,4S,5R)-2,3:4,5-di-O-isopropylidene-1-O-trityl-1,2,3,4,5-pentaoxo-7-octene