4-Toluenesulfonyl chloride → Tert-butyl 4-(pyrimidin-2-yl)-2-(tosyloxymethyl)-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate

Participants

Reaction Steps

To a solution of tert-butyl 10-(hydroxymethyl)-8-pyrimidin-2-yl-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (1.45 g, 3.98 mmol) in dichloromethane (15 mL) was added triethylamine (1.66 mL, 11.9 mmol) and 4-(dimethylamino)-pyridine (195 mg, 1.59 mmol) at 0° C. Tosyl chloride (910 mg, 4.78 mmol) was then added in one portion. The reaction mixture was allowed to warm to room temperature and stirred for 16 h. The reaction mixture was quenched with water and the layers were separated. The aqueous layer was extracted with dichloromethane, and the combined organic layers washed with saturated sodium bicarbonate solution and brine. The organic layer was dried over Na2SO4, filtered and concentrated in vacuo. Silica gel column chromatography (0-80% ethyl acetate/hexanes) provided tert-butyl 4-(pyrimidin-2-yl)-2-(tosyloxymethyl)-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate (1.83 g, 3.53 mmol, 89%). ESI-MS m/z calc. 518.2. found 519.3 (M+1)+; Retention time: 1.83 minutes (3 min run). 1H NMR (400 MHz, MeOD) δ 8.31 (d, J=4.8 Hz, 2H), 7.82 (d, J=8.3 Hz, 2H), 7.45 (d, J=8.2 Hz, 2H), 6.60 (t, J=4.8 Hz, 1H), 4.67-4.48 (m, 2H), 4.12 (d, J=4.6 Hz, 2H), 3.89 (ddd, J=12.0, 7.5, 4.6 Hz, 1H), 3.71-3.56 (m, 2H), 3.05 (ddd, J=20.6, 17.0, 8.8 Hz, 2H), 2.80-2.65 (m, 2H), 2.46 (s, 3H), 1.88 (d, J=14.1 Hz, 1H), 1.50 (dt, J=7.9, 4.0 Hz, 2H), 1.45 (s, 9H), 1.38-1.27 (m, 1H).

Provenance & Evidence