Imidazole → tert-butyl (2S)-2-fluoro-3-iodopropylcarbamate

Participants

Reaction Steps

Imidazole (19.8 g, 0.29 mol) was dissolved in methylene chloride (900 mL) at room temperature. Iodine (73.9 g, 0.29 mol) was added and the reaction mixture was stirred for 10 min at room temperature and then cooled to 0° C. Triphenylphosphine (76.3 g, 0.29 mol) was added portionwise over 10 min such that the internal temperature remained below 10° C. A solution of tert-butyl (2S)-2-fluoro-3-hydroxypropylcarbamate (45.0 g, 0.23 mol) in methylene chloride (300 mL) was added dropwise. The reaction mixture was allowed to warm to room temperature and stirring was continued for 12 h. The reaction mixture was filtered through a pad of Celite® and washed with additional methylene chloride. The filtrate was concentrated under reduced pressure and purified by silica gel column chromatography eluting with methylene chloride. This procedure afforded tert-butyl (2S)-2-fluoro-3-iodopropylcarbamate as a colorless oil (42.5 g, 62%). 1H NMR (300 MHz, CDCl3) δ 4.80–5.10 (br s, 1H), 4.58–4.72 (m, 0.5H), 4.42–4.56 (m, 0.5 H), 3.48–3.70 (m, 1H), 3.20–3.46 (m, 3H), 1.48 (s, 9H).

Provenance & Evidence