Trifluoro-methanesulfonic acid (6S,7R,7aR)-6-isopropenyl-3-oxo-tetrahydro-pyrrolo[1,2-c]oxazol-7-yl ester

(2R,3R,4S)-N-tert-butyloxycarbonyl-4-benzoyloxy-3-hydroxy-2-(tert-butyldiphenylsiloxymethyl)pyrrolidine

(2R,3R,4S)-N-tert-butoxycarbonyl-2-tert-butyldiphenylsilyloxymethyl-3,4-isopropylidenedioxypyrrolidine