CID 16711988 → Tert-butyl 5-fluorospiro[indoline-3,3'-piperidine]-1'-carboxylate

To a stirred solution of tert-butyl 5-fluoro-2-oxospiro[indoline-3,3′-piperidine]-1′-carboxylate (0.80 g, 2.5 mmol) in toluene (20 mL) was added dropwise a solution of sodium bis(2-methoxyethoxy)aluminium hybrid (Red-Al) in toluene (65% w/w, 1.1 mL, 3.5 mmol) at about 70° C. under N2. The reaction mixture was stirred at about 75° C. for 3 h. After cooling, the reaction mixture was quenched with EtOAc and concentrated in vacuo. The residue was diluted with EtOAc, washed with water and brine, dried and concentrated. The residue was purified by column chromatography (hexane:EtOAc, 3:1) to give tert-butyl 5-fluorospiro[indoline-3,3′-piperidine]-1′-carboxylate (0.18 g, 24%) as an oil. LCMS (APCI+) m/z 307 [M+H]+; Rt=3.66 min.