Sodium Bicarbonate → O-(3-(t-Butoxycarbonyl)propanoyloxy)methyl S-ethyl carbonothioate

Participants

Reaction Steps

To a mixture of acid 1 (1.0 g, 5.74 mmol) in H2O (14.5 mL), and CH2Cl2 (14.5 mL) was added NaHCO3 (1.00 g, 11.9 mmol) and TBAHSO4 (1.95 g, 5.74 mmol). After stirring for 25 min, S-ethyl O-iodomethyl carbonothioate (1.10 g, 4.42 mmol, prepared according to Synthesis 1990, 1159) in CH2Cl2 (5 mL) was added. The biphasic reaction was stirred vigorously for 2 h 35 min and was diluted with water and CH2Cl2. The layers were separated, the organic layer was washed with water, 0.5 N HCl solution, saturated NaHCO3 solution, saturated NaCl solution, dried over Na2SO4, filtered and concentrated to dryness. The crude product was triturated with Et2O and the solids were removed by filtration and rinsed with small portions of Et2O. After concentration, the combined filtrates were purified by flash chromatography on silica gel, using 20% EtOAc in hexanes as eluent to furnish compound 2 (1.06 g, 82%) as a colorless oil. 1H NMR (400 MHz, CDCl3) δ 1.33 (t, J=7.4 Hz, 3H), 1.44 (s, 9H), 2.54-2.58 (m, 2H), 2.63-2.66 (m, 2H), 2.89 (q, J=7.4 Hz, 2H), 5.62 (s, 2H).

Provenance & Evidence