反应详情

温度

0 °C

To a solution of ester prepared in Example 24 (3.80 g, 15.2 mmol) in CH2Cl2 (100 mL) was added DIBAL-H (33.4 mL, 33.4 mmol of a 1.0 M solution in toluene) at −78° C. After 15 minutes, the solution was warmed to 0° C. and stirred for an additional 90 minutes. An aqueous solution of 2N HCl (50 mL) was then added dropwise to quench the excess DIBAL-H. The solvent layers were separated and the aqueous layer extracted with CH2Cl2 (2×200 mL). The combined organic layers were dried (MgSO4), filtered, and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (5:2 hexanes/EtOAc) to yield the title compound (2.5 g, 74%) as a yellowish oil that solidified upon standing. (C6H8BrNOS): LC-MS, RT 1.38 min, M+H 221.0; 1H NMR (CDCl3): δ 2.31 (s, 3H), 2.82 (t, 2H), 2.90-3.00 (broad s, 1H), 3.89 (t, 2H).

1. customto quench the excess DIBAL-H
2. customThe solvent layers were separated
3. extractionthe aqueous layer extracted with CH2Cl2 (2×200 mL)
4. dry with materialThe combined organic layers were dried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by silica gel flash chromatography (5:2 hexanes/EtOAc)