4-Methylmorpholine → (S)-tert-Butyl 2-((tert-butoxycarbonyl)amino)-4-hydroxybutanoate

Participants

Reaction Conditions

Reaction Steps

To a solution of Boc-L-Asp-OtBu (3.00 g, 10.4 mmol) in 1,2-dimethoxyethane (10 mL) was added at −15° C. 4-methylmorpholine (1.14 mL, 10.4 mmol) and isobutyl chloroformate (1.35 mL, 10.4 mmol). After stirring for 10 min at −15° C. the precipitate was filtered off and washed with cold 1,2-dimethoxyethane (20 mL). To the filtrate was added at −15° C. a solution of sodium borohydride (0.59 g, 15.6 mmol) in water (5 mL). After 5 min water (250 mL) was added. The reaction mixture was extracted with ethyl acetate (3×100 mL), the combined organic layers dried over sodium sulphate, and concentrated under reduced pressure to give the title compound.

Provenance & Evidence