Iodine → HCID 59382885, compound

Participants

Reaction Steps

A 50 mL three-necked flask was charged with magnesium turning (240 mg, 10 mmol) and a small crystal of iodine. The flash was evacuated and refilled with N2. A portion of a solution of 1-bromo-2-cyclopropylmethyl-3-fluoro-benzene (2.1 g, 8.57 mmol) in dry THF (10 mL) was added dropwise to trigger the reaction. When the color of iodine had disappeared, the residual solution was added dropwise slowly. The mixture was stirred under reflux for 2.5 h and most of magnesium was consumed. The resulting Grignard reagent was used for the next step. To another 100-mL three-necked flask was added (R)-tert-butyl 3-(methoxy(methyl)-carbamoyl)piperidine-1-carboxylate (1.55 g, 5.7 mmol) and THF (15 mL). The flask was evacuated and refilled with N2. The mixture was cooled in a dry ice-acetone bath and the Grignard reagent prepared above (10 mL) was added slowly. The reaction mixture was stirred at −20 to −10° C. for 2.5 h. The mixture was quenched with sat'd aq NH4Cl (20 mL), extracted with EtOAc (3×), and the combined organic layers were dried over Na2SO4. Solvent removal and flash column chromatography, eluting with 5% EtOAc/PE afforded (R)-tert-butyl 3-(2-(cyclopropylmethoxy)-3-fluorobenzoyl)piperidine-1-carboxylate (1.5 g, 70%). 1H NMR (400 MHz, CDCl3): 0.27 (m, 2H), 0.57 (m, 2H) 1.20 (m, 1H), 1.43 (s, 9H), 1.60-1.51 (m, 4H), 1.73 (m, 1H), 2.02 (m, 1H), 2.79 (m, 1H), 3.47 (m, 1H), 3.98 (m, 3H), 4.20 (m, 1H), 7.04 (m, 1H), 7.20 (m, 2H). MS (E/Z): 378 (M+H+).

Provenance & Evidence