Methanol → (9H-fluoren-9-yl)methyl 4-hydroxy-2-(hydroxymethyl)pyrrolidine-1-carboxylate

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Reaction Steps

1-(((9H-Fluoren-9-yl)methoxy)carbonyl)-4-hydroxypyrrolidine-2-carboxylic acid (13.3 g, 37.6 mmoles) is dissolved in anhydrous tetrahydrofuran (250 mL). The solution is stirred at ambient temperature, and borane-methyl sulfide complex in tetrahydrofuran (2 M, 40 mL, 80 mmoles) is added slowly via syringe. When the evolution of gas ceases, the flask is fitted with a condenser and Drierite drying tube and the solution is refluxed for 1 hour. During this time a white precipitate forms. Methanol (15 mL) is carefully added to the hot reaction mixture, which is refluxed for an additional 15 minutes, during which time the solid dissolves. The mixture is cooled and evaporated to a clear syrup. The syrup is coevaporated three times with methanol (100 mL each) to remove borate salts. The resulting brittle white solid is dried in vacuo. The yield is 12.7 g (99%).

Provenance & Evidence