Iodine → HCID 59383064, compound

Participants

Reaction Steps

A flame dried 50 mL three-necked flask was charged with magnesium turnings (380 mg, 15.8 mmol) and a small crystal of iodine in THF (5 mL). The flask was evacuated and refilled with N2. Then a solution of 1-chloro-4-methoxybutane (1.6 g, 13.2 mmol) in THF (10 mL) was added dropwise slowly to the mixture. The reaction mixture was stirred under reflux for 2.5 h and most of the magnesium was consumed. The resulting Grignard reagent was used as follows. To another 100 mL three-necked flask was added (R)-tert-butyl 3-(2-(cyclopropylmethoxy)-3-fluorobenzoyl)piperidine-1-carboxylate (0.5 g, 1.32 mmol) and THF (10 mL). The flask was evacuated and refilled with N2. The mixture was cooled with a dry ice-acetone bath and the Grignard reagent (250 mL) was added. The reaction mixture was allowed to warm slowly to rt while stirring overnight. The mixture was quenched with sat'd aq NH4Cl (10 mL), extracted with EtOAc (3×), and the combined organic layers were dried over Na2SO4 Evaporation of the solvent and purification by flash column chromatography, eluting with 10% EtOAc/PE afforded (R)-tert-butyl 3-((S)-1-(2-(cyclopropylmethoxy)-3-fluorophenyl)-1-hydroxy-5-methoxypentyl)piperidine-1-carboxylate (560 mg, 91%). 1H NMR (400 MHz, CDCl3): 0.35 (m, 2H), 0.63 (m, 2H), 1.05 (m, 1H), 1.43 (s, 9H), 1.55-1.20 (m, 9H), 1.85 (m, 1H), 2.55 (m, 1H), 2.67 (m, 1H), 3.27 (s, 3H), 3.33 (m, 2H), 3.85 (m, 1H), 4.05 (m, 2H), 4.25 (m, 1H), 6.97 (m, 3H). MS (E/Z): 466 (M+H+).

Provenance & Evidence