Potassium Permanganate → Tert-butyl 4-oxo-3,4-dihydro-2H-spiro[naphthalene-1,4'-piperidine]-1'-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of the Boc-piperidine (602 mg, 2 mmol) in acetonitrile (10 ml) was added potassium permanganate (KMnO4, 950 mg, 6 mmol). The reaction mixture was stirred at 70° C. for 15 hours, filtered through Celite, and the filter cake was washed with dichloromethane. The filtrate and washings were concentrated and the residue was dissolved in acetonitrile (10 ml) and reacted with KMnO4 (950 mg, 6 mmol) at 70° C. for another 24 hours. After filtration, washing and concentrating, the residue was purified by flash column chromatography (CH2Cl2/CH3CN: 1:0 to 9:1) to provide tert-butyl 4-oxo-3,4-dihydro-2H-spiro[naphthalene-1,4′-piperidine]-1′-carboxylate (A4). LC-MS: m/e=260.0 (M+H−tBu). Rt=3.46 min. 1H-NMR (500 MHz, CDCl3): 8.07 (dd, J=1.5, 7.8, 1H), 7.60-7.57 (td, J=7.9, 1.2, 1H), 7.50 (d, J=7.9, 1H), 7.36 (t, J=7.6, 1.0, 1H), 4.10 (br.d, J=13.2, 2H), 3.08 (t, J=13.8, 2H), 2.71 (t, J=6.7, 2H), 2.27 (t, J=6.9, 2H), 2.05 (td, J=13.4, 4.7, 2H), 1.73 (br.d, J=13.2, 2H), 1.52 (s, 9H).

Provenance & Evidence