Hydrogen Peroxide → Benzyl 2-(di-tert-butoxyphosphoryloxy)ethylcarbamate

Participants

Reaction Steps

Tetrazole (3 wt % solution in CH3CN, 32 mL, 11.0 mmol) and di-tert-butyl N,N-diisopropylphosphoramidite (95%, 2.73 mL, 8.2 mmol) were added to a solution of benzyl N-2-hydroxyethylcarbamate (224) (1.07 g, 5.48 mmol) in THF (20 mL) and the mixture was stirred at room temperature for 16 h. The mixture was cooled to 0° C. and H2O2 (70% aqueous, 1.0 mL, 24 mmol) was added. After 15 min. the cooling bath was removed and the mixture was stirred for a further 6 h, then aqueous Na2SO3 (10%, 50 mL) was added with water bath cooling. After 25 min the organic solvents were removed under reduced pressure and the aqueous residue was extracted with EtOAc (×2). The combined extracts were washed with brine, dried, and evaporated. The residue was purified by chromatography, eluting with EtOAc/petroleum ether (1:1) to give benzyl 2-{[di(tert-butoxy)phosphoryl]oxy}ethylcarbamate (225) (1.36 g, 64%) as a colourless oil: 1H NMR [CDCl3] δ 7.37-7.28 (m, 5H), 5.43 (br 9, 1H), 5.11 (s, 2H), 4.07-4.00 (m, 2), 3.46 (q, J=5.1 Hz, 2H), 1.47 (s, 18H). HRMS (FAB) calcd. for C18H31NO6P (M+) m/z 388.1889, found 388.1889.

Provenance & Evidence