Imidazole → Ethyl (S)-(-)-2-(tert-butyldimethylsilyloxy)propionate

Participants

Reaction Steps

To a solution of (S)-ethyl lactate (11.8 g, 100 mmol) in DMF (50 mL) was added imidazole (10.2 g, 150 mmol). The mixture was cooled in an ice bath and tert-butyldimethylsilyl chloride (15.8 g, 105 mmol) was added in three portions, at intervals of 30 min between each addition. The reaction mixture was stirred overnight. The reaction mixture was diluted with water (30 mL) and extracted with Et2O (50 mL×2). The combined extracts were washed with brine, dried over MgSO4 and concentrated in vacuo. The residue was distilled under vacuum (bp 70-78° C., 0.5 mmHg) to afford 22.07 g (95%) of (S)-ethyl 2-(tert-butyldimethylsilyloxy)propanoate: 1H NMR (400 MHz, CHLOROFORM-d) δ 4.32 (q, J=6.6 Hz, 1H), 4.11-4.25 (m, 2H), 1.40 (d, J=6.6 Hz, 3H), 1.29 (t, J=7.1 Hz, 3H), 0.93 (s, 9H), 0.12 (s, 3H), 0.09 (s, 3H).

Provenance & Evidence