Ammonia → HCID 59810892, compound

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Reaction Steps

In a flask purged with ammonia gas, about 150 mL of liquid ammonia is collected with ammonia condenser at −78° C. To the liquid ammonia is added portion wise lithium metal (116 mmol; 805 mg) at the same temperature. To the deep blue solution is added a solution of (2R,4R)-4-benzyloxy-2-ethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (29.1 mmol; 8.90 g) and tert-butanol (58.2 mmol; 4.31 g) in THF (30 mL). After stirring for 2 hours, the reaction mixture is quenched with MeOH, and then warmed to ambient temperature. The mixture is diluted with water, then aqueous 1M HCl is added to reach pH 8-9. The product is extracted three times with EtOAc. The combined organic layer is washed with brine, dried over MgSO4, filtered, concentrated under reduced pressure to give (2R,4R)-4-hydroxy-2-ethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (6.25 g, 99.8%).

Provenance & Evidence