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 ethyl acetate (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