反应详情

温度

0 °C

While under an argon atmosphere, a solution of 3-benzyl 4-ethyl 2,2-dimethyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)oxazolidine-3,4-dicarboxylate (350 mg, 0.72 mmol) in dichloromethane (5 mL) was cooled to −40° C. and carefully treated with trimethylsilyltrifluoromethane sulfonate (1.09 g, 4.29 mmol, 0.94 mL). After stirring for 30 minutes the solution was warmed to 0° C. and stirred an additional 2 h, concentrated and purified using a combiflash system (12 g silica gel column, eluting with 20-100% ethyl acetate in heptanes) to give ethyl 2-(benzyloxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate (180 mg, 56%). 1HNMR (CDCl3) δ 7.38-7.31 (m, 5H), 5.81 (bs, 1H), 5.10 (s, 2H), 4.25-4.23 (m, 3H), 3.84 (d, 1H), 2.84 (m, 1H), 1.76-1.68 (m, 1H), 1.41-1.35 (m, 2H), 1.28 (t, 3H), 1.23 (s, 12H), 1.11-1.03 (m, 1H), 1.29 (m, 4H), 0.75 (t, 2H). MS found for C23H36BNO7 m/z[450 (M+1)].

1. stirringstirred an additional 2 h
2. concentrationconcentrated
3. custompurified
4. washa combiflash system (12 g silica gel column, eluting with 20-100% ethyl acetate in heptanes)