1-Bromo-3-chloro-5-fluorobenzene → (R)-tert-butyl 3-(3-chloro-5-fluorobenzoyl)piperidine-1-carboxylate

A solution of 1-bromo-3-chloro-5-fluoro-benzene (31.5 g, 0.15 mol) in anhydrous THF (120 mL) was added dropwise to the Mg (5.4 g, 0.22 mol) at rt under nitrogen. The mixture was stirred at 50-60° C. for 1 hr until most of the magnesium was consumed. 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 (20.4 g, 0.075 mol) in anhydrous THF (200 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-chloro-5-fluorobenzoyl)piperidine-1-carboxylate (25 g, 98%), which was used in the next step without further purification.

1. customwas consumed
2. additionAfter addition
3. customThe mixture was quenched with saturated NH4Cl solution (300 mL)
4. extractionextracted with EtOAc (3×200 mL)
5. washThe combined organic layers were washed with brine
6. dry with materialdried over Na2SO4
7. concentrationconcentrated in vacuo

ORD-Eintrag

ord-160f9ff66c204ff6a59abdb3817ee3cd

Quelldatensatz

uspto-grants-2013_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08487108B2