Potassium Carbonate → Fmoc-Hyp(OEt)-OH

Participants

Reaction Steps

(2S,4R)-4-Ethoxypyrrolidine-2-carboxylic acid hydrochloride (Compound SP820) (45 g, 230 mmol) was dissolved in a mixture of 1,4-dioxane (500 ml) and water (500 ml), potassium carbonate (79.4 g, 574 mmol) and (9H-fluoren-9-yl)methyl (2,5-dioxopyrrolidin-1-yl) carbonate (Fmoc-OSu, 69.8 g, 207 mmol) were added, and the mixture was stirred at room temperature for 2 hours. The reaction solution was washed with diethyl ether, and the aqueous layer was adjusted to pH 3 with an aqueous potassium bisulfate solution and extracted with ethyl acetate. The resulting organic extract was washed with brine, dried over sodium sulfate and then concentrated under reduced pressure to afford (2S,4R)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)-4-ethoxypyrrolidine-2-carboxylic acid (Compound SP813, Fmoc-Hyp(Et)-OH) (90.7 g, 103%).

Provenance & Evidence