(3R,6R)-6-((R)-2-tert-Butoxycarbonyl-5-oxo-pyrrolidin-1-yl)-3-methyl-3,6-dihydro-[1,2]oxazine-2-carboxylic acid benzyl ester

(3aR,4S,6aS)-2,2,4-Trimethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyrrole-5-carboxylic acid benzyl ester

(R)-5-Oxo-1-((3aR,4R,7aR)-2,2,7-trimethyl-3a,7a-dihydro-4H-1,3,5-trioxa-6-aza-inden-4-yl)-pyrrolidine-2-carboxylic acid tert-butyl ester

(R)-5-Oxo-1-((3aR,4R,7S,7aR)-2,2,7-trimethyl-tetrahydro-1,3,5-trioxa-6-aza-inden-4-yl)-pyrrolidine-2-carboxylic acid tert-butyl ester

(3aR,4S,6aS)-2,2,4-Trimethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyrrole

(3R,4R,5R,6R)-6-((R)-2-tert-Butoxycarbonyl-5-oxo-pyrrolidin-1-yl)-4,5-dihydroxy-3-methyl-[1,2]oxazinane-2-carboxylic acid benzyl ester

4-amino-1,4,5-trideoxy-L-lyxofuranose-1-sulfonic acid

(R)-5-Oxo-1-((3aR,4R,7R,7aR)-2,2,7-trimethyl-tetrahydro-1,3,5-trioxa-6-aza-inden-4-yl)-pyrrolidine-2-carboxylic acid tert-butyl ester