Реакция #214747

Уравнение реакции

pyridine

3-benzyloxy-6,6-ethylenedioxy-2-methyl-2-(4'-methyl-5'-hydroxypentyl)-oxepane

→

3-benzyloxy-6,6-ethylenedioxy-2-methyl-2-(4'-methyl-5'-oxopentyl)-oxepane

Выход 83.1%

Растворители

methylene chloride

methylene chloride

Условия реакции

Обработка

1. 1
   workup.ADDITIONcelite (13 g) is added
2. 2
   ФильтрацияThe mixture is then filtered
3. 3
   Промывкаthe celite cake is washed with methylene chloride (10×50 ml)
4. 4
   Промывкаwashed with saturated sodium bicarbonate (2×150 ml)
5. 5
   ДругоеThe methylene chloride phase is separated
6. 6
   Сушкаdried (MgSO4)
7. 7
   Другоеthe solvents are removed at reduced pressure
8. 8
   ДругоеThe crude product (1.3 g) is chromatographed on SilicAR CC-7 (25 g, Mallinckrodt) in hexane
9. 9
   ПромывкаElution with 7-10% ethyl acetate/hexane

Методика

A solution of pyridine (3.6 g, 0.0444 mol) and chromium trioxide (2.2 g, 0.0222 mol) in methylene chloride (450 ml) at 23° C. in a nitrogen atmosphere is stirred for 45 minutes. The mixture is cooled to -10° C. and celite (13 g) is added followed by (2S*, 3R*)-3-benzyloxy-6,6-ethylenedioxy-2-methyl-2-(4'-methyl-5'-hydroxypentyl)-oxepane (1.4 g, 0.0037 mol) in methylene chloride (150 ml). The mixture is stirred for 1 hour at -10° C. and 30 minutes at 0° C. The mixture is then filtered and the celite cake is washed with methylene chloride (10×50 ml). The filtrate and washings are combined and washed with saturated sodium bicarbonate (2×150 ml). The methylene chloride phase is separated, dried (MgSO4) and the solvents are removed at reduced pressure. The crude product (1.3 g) is chromatographed on SilicAR CC-7 (25 g, Mallinckrodt) in hexane. Elution with 7-10% ethyl acetate/hexane gives (2S*, 3R*)-3-benzyloxy-6,6-ethylenedioxy-2-methyl-2-(4'-methyl-5'-oxopentyl)-oxepane as a clear colorless oil (1.157 g, 83%).

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