L-Hydroxyproline → (2S,4R)-1-[(9H-fluoren-9-ylmethoxy)carbonyl]-4-hydroxypyrrolidine-2-carboxylic acid

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Reaction Steps

To a suspension of H-trans-Hyp-OH (122.5 g, 362 mmol) in THF/H2O (100 mL/200 mL) is added 2N Na2CO3 (250 mL), along with addition of a suspension of Fmoc-OSu in THF (700 mL). The mixture is stirred at room temperature overnight. The mixture is diluted with H2O (2700 mL) and extracted with ether/petroleum ether (500 mL/500 mL) The aqueous layer is acidified by 6N HCl and then extracted with ethyl acetate (1×1000 mL, 1×500 mL). The combined extract is washed with brine once and dried over Na2SO4. After removal of most of solvent, the residue is treated with ethyl ether (200 mL). The white solid is filtered and dried under vacuum. Yield: 125.8 g (356 mmol, 98%)

Provenance & Evidence