Sodium borohydride → (R)-3-(((benzyloxy)carbonyl)amino)-4-hydroxybutanoic acid

Participants

Reaction Steps

A solution of (R)-benzyl 2,5-dioxotetrahydrofuran-3-ylcarbamate (INTERMEDIATE 1, 53.28 g, 213.79 mmol) in THF (330 ml) was added over a 4 hour period using an additional funnel to a mixture of sodium borohydride (8.09 g, 213.79 mmol) in THF (330 ml) at 0° C. After the addition was complete, the mixture was warmed to room temperature and stirred for 2 hours. The solution was then concentrated under reduced pressure to ¼ of the original volume, cooled to 0° C., and carefully quenched by the slow addition of water (400 ml). The mixture was acidified to pH 4 with 1N aqueous hydrochloric acid and extracted with Et2O (5×300 ml). The combined organic layers were dried (Na2SO4) and concentrated in vacuo to provide the title product (45.9 g, yield: 85%).

Provenance & Evidence