Triethylamine → Benzyl (2S,4R)-4-methoxy-2-{[(methylsulfonyl)oxy]methyl}-1-pyrrolidinecarboxylate

Participants

Reaction Conditions

Reaction Steps

Methanesulfonyl chloride (0.175 mL, 2.26 mmol, 1.2 equiv) was added to a solution of (2S,4R)-2-(hydroxymethyl)-4-methoxy-1-pyrrolidinecarboxylate (3-3, 0.500 g, 1.88 mmol, 1 equiv) and triethylamine (0.394 mL, 2.83 mmol, 1.50 equiv) in dichloromethane (30 mL) at 0° C. The resulting mixture was warmed to 23° C. and stirred for 1 h. The reaction mixture was partitioned between saturated sodium bicarbonate solution and dichloromethane (2×40 mL). The combined organic layers were dried over sodium sulfate and concentrated. The residue was purified by flash column chromatography (100% hexane initially, grading to 100% EtOAc) to provide benzyl (2S,4R)-4-methoxy-2-{[(methylsulfonyl)oxy]methyl}-1-pyrrolidinecarboxylate (3-4) as a light yellow oil. 1H NMR (300 MHz, CDCl3) major rotamer: δ 7.37-7.25 (br m, 5H), 5.17 (d, 1H, J=11.8 Hz), 5.10 (d, 1H, J=11.8 Hz), 4.65 (dd, 1H, J=8.3, 3.8 Hz), 4.24 (br m, 2H), 3.95 (m, 1H), 3.68 (br d, 1H, J=12.0 Hz), 3.45 (dd, 1H, J=12.0, 4.4 Hz), 3.30 (s, 3H), 2.88 (s, 3H), 2.39 (m, 1H), 2.12 (m, 1H).

Provenance & Evidence