反应详情

To a solution of 200g (1.92 mol) of methyl (2S)-lactate (5) and 295 g (2.11 mol) of triethylamine in toluene (1 L) at 0° C. was added 270 mL, 2.11 mol) of benzenesulfonyl chloride dropwise over a 2 hour period under a nitrogen atmosphere. The cooling bath was removed and the reaction mixture was allowed to warm to room temperature and stir there overnight. The reaction was worked-up by washing with water (3×1 L) and dried (MgSO4). Filtration, concentration and purification by vacuum distillation afforded 440 g (94%) of methyl (2S)-2-(phenylsulfonyl)oxypropanate (12) as a pale yellow liquid: bp 140°-142° C. (0.1 mm Hg); 1H NMR (CDCl3) δ1.51-1.56 (d, 3 H), 3.66 (s, 3 H), 4.95-5.01 (q, 1 H), 7.54-7.59 (m, 2 H), 7.65-7.70 (m, 1 H), 7.93-7.95 (d, 2 H); 13C NMR (CDCl3) δ169.3, 133.9, 129.1, 127.7, 112.3, 74.2, 52.5, 18.3; IR (neat) 2958 (w), 1762 (s), 1586 (m), 1451 (s), 1190 (vs), 1084 (s), 926 (m), 753 (m) cm-1.

1. customThe cooling bath was removed
2. washby washing with water (3×1 L)
3. dry with materialdried (MgSO4)
4. filtrationFiltration, concentration and purification
5. distillationby vacuum distillation