tert-butyl (2R,3R,4R)-4-azido-3-hydroxy-2-hydroxymethylpyrrolidine-1-carboxylate

tert-butyl (2R,3S,4R)-4-tert-butoxycarboxamido-2-tert-butyldiphenylsilyloxymethyl-3-mesyloxy-pyrrolidine-1-carboxylate