Реакция #547605

Уравнение реакции

CH2Cl2

CH2Cl2

ethyl benzene

acetic anhydride

→

acetophenone

Выход 96.1%

Растворители

CH3CN

CH3CN

Условия реакции

Обработка

1. 1
   Другоеto give a deep orange solution which
2. 2
   workup.WAITis stable at −40° C. for several hours
3. 3
   workup.ADDITIONwas added in one portion to the solution of starting material
4. 4
   Другоеquenched by addition of saturated aqueous Na2SO4
5. 5
   Экстракцияextracted with EtOAc
6. 6
   Промывкаwashed with water, brine
7. 7
   Сушкаdried over Na2SO4
8. 8
   Концентрированиеconcentrated
9. 9
   Другоеpurified by silica gel column chromatography

Методика

To a freshly prepared CH2Cl2 solution of chromyl diacetate (O2Cr(OAc)2, 1 mL, 1 M) was added dropwise a CH3CN solution of H5IO6 (0.33 M, 3 mL) at −40° C. for 10 minutes to give a deep orange solution which is stable at −40° C. for several hours. In a different flask, a CH2Cl2 (0.4 mL) solution of ethyl benzene (212 mg, 2 mmol) and acetic anhydride (0.38 mL, 4 mmol, 2 eq) was cooled to −40° C. The earlier prepared chromium oxidant solution (0.4 mL, 0.25 M. 5 mol %) was added in one portion to the solution of starting material, followed; by the addition of a CH3CN solution of H5IO6 (0.33 M, 18.2 mL, 3 eq) at −40° C. over a period of 30 minutes. The resulting orange colored reaction mixture was gradually warmed up to 0° C. for a period of 1.5 h, quenched by addition of saturated aqueous Na2SO4, extracted with EtOAc, washed with water, brine, dried over Na2SO4, concentrated and purified by silica gel column chromatography to give acetophenone (231 mg, 96%).

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