[CH2:1]([Mg][Cl:6])[CH2:2][CH2:3][CH3:4].[CH3:7][N:8]([CH3:21])[C:9]1(C#N)[CH2:18][CH2:17][C:12]2([O:16][CH2:15][CH2:14][O:13]2)[CH2:11][CH2:10]1.[Cl-].[NH4+].Cl[Si](C)(C)C>O1CCCC1.O>[ClH:6].[CH2:1]([C:9]1([N:8]([CH3:21])[CH3:7])[CH2:18][CH2:17][C:12]2([O:16][CH2:15][CH2:14][O:13]2)[CH2:11][CH2:10]1)[CH2:2][CH2:3][CH3:4]2M n-butylmagnesium chloride solution in THF (228 ml, 0.456 mole) was slowly added under argon and while cooling with an ice/salt mixture to a solution of 8-dimethylamino-1,4-dioxa-spiro[4.5]decane-8-carbonitrile (38.3 g, 0.182 mole) in absolute tetrahydrofuran (420 ml). In this connection the reaction temperature should not rise above 10° C. The reaction mixture was then stirred for 16 hours at room temperature, a brownish clear solution being formed. The reaction mixture was worked up by the dropwise addition of saturated ammonium chloride solution (150 ml) while cooling with ice (0°-10° C.). A white solid was thereby formed, which was dissolved by adding water (approximately 250 ml). The reaction mixture was extracted with diethyl ether (4×100 ml). The organic phase was washed with water (100 ml) and saturated NaCl-Solution (100 ml), dried and concentrated by evaporation. A yellow oil (44.5 g) remained, which apart from the desired butyl compound also contained the educt nitrile. The crude product was dissolved in ethyl methyl ketone (275 ml), ClSiMe3 (32 ml, 0.245 mole) was added while cooling with ice, and the mixture was stirred in an open flask at room temperature. The hydrochloride was separated by filtering several times at 2-hourly intervals. After a reaction time of 6 to 8 hours (8-butyl-1,4-dioxa-spiro[4.5]dec-8-yl)-dimethylamine hydrochloride was isolated in a yield of 82% (41.8 g) as a white solid.
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