反应详情

While under an argon atmosphere, a solution of chloro(1,5-cyclooctadiene) iridium(I) dimer (15 mg, 0.022 mmol) and 1,2-bis(diphenyl-phosphino) ethane (18 mg, 0.044 mmol) in dichloromethane (5 mL) was treated with pinacol borane (225 mg, 1.76 mmol, 0.26 mL) and stirred for 15 minutes. To this mixture was added a solution of 3-benzyl 4-ethyl 4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylate (530 mg, 1.47 mmol) in dichloromethane (5 mL). After stirring for 19 h at room temperature the solution was concentrated and purified using a combiflash system (24 g column, eluting with 5-50% (ethyl acetate in heptanes) to give 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 (470 mg, 65%). 1H NMR (CDCl3) δ: 7.22 (m, 5H), 5.01 (m, 2H), 3.91 (m, 4H), 2.20-2.01 (m, 1H), 1.75 (m, 1H), 1.51 (2s, 6H), 1.29 (m, 4H), 1.16 (s, 12H), 1.02 (t, J=7.2 Hz, 3H), 0.69 (t, 2H). MS found for C26H40BNO7 m/z [490 (M+1), 522 (M+Na)].

1. stirringAfter stirring for 19 h at room temperature the solution
2. concentrationwas concentrated
3. custompurified
4. washeluting with 5-50% (ethyl acetate in heptanes)