[CH2:1]1[C:4]2([CH2:7][NH:6][CH2:5]2)[CH2:3][O:2]1.[Br:8][C:9]1[CH:16]=[CH:15][C:12]([CH2:13]Br)=[CH:11][CH:10]=1.C(=O)([O-])[O-].[K+].[K+]>C1COCC1.[I-].[Na+]>[Br:8][C:9]1[CH:16]=[CH:15][C:12]([CH2:13][N:6]2[CH2:7][C:4]3([CH2:3][O:2][CH2:1]3)[CH2:5]2)=[CH:11][CH:10]=1A mixture of 2-oxa-6-aza-spiro[3.3]heptane (˜3.72 mmol), 4-bromobenzyl bromide (0.39 g, 1.54 mmol), potassium carbonate (0.64, 4.63 mmol) and sodium iodide (11 mg, 0.08 mmol) in THF (10 mL) was stirred at ambient temperature for 16 h. The solid was removed by filtration, washed with THF and the combined filtrate was evaporated. The resultant residue was purified by flash chromatography (silica, 12 g column, ISCO, 0-100% ethyl acetate in pentane then 10% methanol in DCM) to afford the title compound (0.28 g, 68%) as a viscous oil which crystallised on standing to a pale yellow solid. 1H NMR (CDCl3, 300 MHz): 7.46-7.40 (m, 2H), 7.15-7.09 (m, 2H), 4.73 (s, 4H), 3.48 (s, 2H), 3.35 (s, 4H).
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