Allyl bromide → (S)-3-(Allyloxy)-2-((tert-butoxycarbonyl)amino)propanoic acid

Participants

Reaction Conditions

Reaction Steps

N-tert-butoxycarbonyl L-serine (27.04 g, 0.1318 mol) was dissolved in DMF (220 mL). The solution was cooled to 0° C. (icebath) before sodium hydride (60% dispersion in mineral oil, 11.59 g, 0.2898 mol) was added slowly under stirring. After gas evolution had ceased allyl bromide (17.54 g, 0.1450 mol) was added dropwise and the reaction mixture stirred for 18 hours at room temperature. The solvent was evaporated and the residue dissolved in H2O (500 mL). The solution was washed with Et2O (2×250 mL), cooled to 0° C. (icebath) and acidified to pH 2.5 by addition of 2M aqueous H2SO4. The resulting solution/suspension was extracted with EtOAc (5×250 mL). The combined organic extracts were dried with anhydrous MgSO4 and the solvent evaporated overnight affording the title compound as a slightly yellow-orange viscous liquid (26.86 g, 83%) with spectral characteristics in accordance with published data;3,4 δH (200 MHz; d6-DMSO) 12.52 (1H, br s, COOH), 6.84 (1H, d, J 8, NH), 5.81 (1H, ddt, J 5, 10 and 17, CH═CH2), 5.20 (1H, ddd, J 1, 3 and 17, CH═CHH), 5.09 (1H, ddd, J 1, 3 and 10, CH═CHH), 4.10 (1H, dt, J 5 and 8, CαH), 3.96-3.92 (2H, dt, J 1 and 5, CH2CH═CH2), 3.56 (2H, d, J 5, CH2), 1.34 (9H, s, (CH3)3); δC (75 MHz; d6-DMSO) 171.9, 155.3, 134.8, 116.5, 78.1, 71.0, 69.1, 53.7, 28.1; m/z (ESI) 268.0 ([M+Na]+)

Provenance & Evidence