反应详情

To a 0° C. solution of tert-butyl 2-(2-hydroxyethyl)-2-phenylmorpholine-4-carboxylate (428 mg, 1.4 mmol), dimethyl sulfoxide (4.0 mL, 56.4 mmol) and diisopropylethylamine (1.3 mL, 7.2 mmol) in 8 mL CH2Cl2 was added SO3.pyr (1.4 g, 8.8 mmol) and the reaction mixture was stirred for 2 h. After the addition of saturated aqueous NaHCO3, the solution was extracted with CHCl3, and passed through a plug of silica gel flushing with 2:1 hex:EtOAc to provide tert-butyl 2-(2-oxoethyl)-2-phenylmorpholine-4-carboxylate (226 mg, 53%) as a clear oil. 1H NMR (400 MHz, CDCl3), δ 9.60 (br. s, 1H), 7.54-7.44 (br., 2H), 7.42-7.37 (m, 2H), 7.30 (m, 1H), 4.25-4.01 (br., 1H), 3.80-3.23 (m, 5H), 3.00-2.81 (m, 2H), 2.73 (br., 1H), 1.47 (br., 9H); ESI-MS 328 (M+H).

1. extractionthe solution was extracted with CHCl3