Sodium Carbonate → HCID 86728182, compound

Participants

Reaction Steps

Intermediate 18A (0.500 g, 2.15 mmol) and sodium carbonate (0.50 g, 4.7 mmol) were combined in THF (10 mL) and treated with benzyl chloroformate (0.31 mL, 2.2 mmol) drop wise over 15 min. The reaction mixture was stirred at rt for 18 h. The mixture was concentrated in vacuo, diluted with DCM and washed with saturated Na2CO3 twice, brine and the organic portion dried over Na2SO4, filtered and concentrated. The residue was purified by ISCO chromatography (EtOAc/Hexanes 0-50%, column 40 g) to give benzyl 5-(3,4-dichlorophenyl)pentan-2-ylcarbamate (440 mg, 1.20 mmol, 56.0%) as a clear oil. HPLC/MS (HPLC Method L): RT=2.32 min, [M+1]+ =366.0. The racemates were separated on chiral prep HPLC (chiral AD 10 micron 4.6×250 mm, 15 min 5% isocratic. A=EtOH/MeOH (50/50). B=Heptane; retention time=9.8 min) to afford Intermediate 18B (220 mg, 0.600 mmol, 28.0%). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.07 (3H, d), 1.32-1.41 (2H, m), 1.51-1.62 (2H, m), 2.42-2.57 (2H, m), 3.62-3.75 (1H, m), 4.42 (1H, br. s.), 5.02 (2H, s), 6.91 (1H, d, J=7.5 Hz), 7.17 (1H, br. s.), 7.23-7.31 (6H, m).

Provenance & Evidence