1-Bromo-3-fluorobenzene → (R)-tert-butyl 3-(3-fluorobenzoyl)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of 1-bromo-3-fluoro-benzene (57.7 g, 0.33 mol) in anhydrous THF (480 mL) was added dropwise to Mg (10.6 g, 0.44 mol) at rt under nitrogen. The mixture was stirred at 50-60° C. for 1 hr. The resulting Grignard reagent was used for the next step. The Grignard reagent was added dropwise to a solution of (R)-tert-butyl 3-(methoxy(methyl)carbamoyl)piperidine-1-carboxylate (60 g, 0.22 mol) in anhydrous THF (600 mL) at −78° C. under nitrogen. After addition, the mixture was allowed to stir at rt for 1.5 hr. The mixture was quenched with saturated NH4Cl solution (300 mL) and extracted with EtOAc (3×200 mL). The combined organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo to give crude (R)-tert-butyl 3-(3-fluorobenzoyl)piperidine-1-carboxylate (67.5 g, 100%), which was used immediately in the next step without purification.

Provenance & Evidence