Synthesis
To a suspension of L-serine methyl ester hydrochloride (1.00 g, 6.43 mmol, 1.00 equiv) in dioxane (5.00 mL) was added an aqueous solution (25.7 mL) of NaHCO3 (1.62 g, 19.3 mmol, 3.00 equiv). Subsequently, a dioxane solution (15.0 mL, diluted with 4.20 mL dioxane) of benzyl chloroformate (Cbz-Cl, 1.10 mL, 7.72 mmol, 1.20 eq.) was added to the reaction system and the reaction was stirred at 25 °C. After 5 hours of reaction, the reaction was quenched with 1 M HCl aqueous solution and the aqueous layer was extracted with ethyl acetate (2×). The organic layers were combined, washed with 10% NaCl aqueous solution, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane solution of 50% ethyl acetate) to afford N-benzyloxycarbonyloxy-L-serine methyl ester (1.50 g, 5.92 mmol, 92% yield) as a colorless oil.
References
[1] Journal of Organic Chemistry, 1996, vol. 61, # 16, p. 5528 - 5531
[2] Organic and Biomolecular Chemistry, 2015, vol. 13, # 26, p. 7177 - 7192
[3] Synthesis, 1996, # 2, p. 189 - 191
[4] Beilstein Journal of Organic Chemistry, 2017, vol. 13, p. 106 - 110
[5] Organic Letters, 2018, vol. 20, # 4, p. 1019 - 1022
