[CH2:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[CH:2]1.C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[C:20]([O:24][C:25]([N:27]([CH2:31][CH2:32]Cl)[CH2:28][CH2:29]Cl)=[O:26])([CH3:23])([CH3:22])[CH3:21]>O1CCCC1>[C:20]([O:24][C:25]([N:27]1[CH2:31][CH2:32][C:1]2([C:9]3[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=3)[CH:3]=[CH:2]2)[CH2:29][CH2:28]1)=[O:26])([CH3:23])([CH3:22])[CH3:21]To a solution of indene (5.1 ml, 0.04 mol) in dry tetrahydrofuran (15 ml), cooled in an ice bath and maintained under an atmosphere of nitrogen, was added lithium bis (trimethylsilyl) amide (82 ml of a 1.0M solution in tetrahydrofuran, 0.08 mol), over 15 minutes. The mixture was stirred in the cold for 30 minutes, then added dropwise to a solution of N-tert-butyloxycarbonylbis (2-chloroethyl)amine (9.9 g, 0.04 mol) in tetrahydrofuran (200 ml), at 0° C. The mixture was stirred for 2 hours at this temperature, then allowed to warm to ambient temperature and stirred for a further 30 minutes. The solvent was removed in vacuo to leave a dark oil, which was chromatographed using 5:1 petrol:ether as the eluant, to give 1'-(tert-butyloxycarbonyl)spiro [indene-1,4'-piperidine] (7.1 g, 58%) as a pale yellow solid. N.M.R. (CDCl3) δ 1.28 (2H, d, J=12 Hz), 1.50 (9H, s), 2.00 (2H, t of d, J=12 and 4 Hz), 3.13 (2H, t of d, J=12 and 2 Hz), 4.20 (2H, m), 6.79 (1H, d, J=6 Hz), 6.84 (1H, d, J=6 Hz), 7.30 (4H, m).
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