Реакция #87466

Уравнение реакции

Triethylamine

oxalyl dichloride

dimethyl sulfoxide

(3R,4S,5S)-3,4,5-tris-benzyloxy-6,6-bis-(4-methoxy-benzyloxymethyl)-tetrahydro-pyran-2-ol

→

(3R,4S,5S)-3,4,5-tris-benzyloxy-6,6-bis-(4-methoxy-benzyloxymethyl)-tetrahydro-pyran-2-one

Выход 72.0%

Растворители

dichloromethane

dichloromethane

dichloromethane

Условия реакции

Обработка

1. 1
   workup.STIRRINGthe resulting mixture was stirred for 30 minutes
2. 2
   Другоеto rise to −60° C
3. 3
   ДругоеThe reaction was quenched by addition of saturated aqueous ammonium chloride solution
4. 4
   Сушкаthe organic phase was dried over magnesium sulfate
5. 5
   Фильтрацияfiltered
6. 6
   Концентрированиеconcentrated under reduced pressure
7. 7
   ДругоеThe crude material was purified by flash chromatography over silica gel eluting with a gradient of 0 to 60% ethyl acetate in heptane
8. 8
   Другоеto produce the product (I-1e) (4 g, 72% yield)

Методика

To a solution of oxalyl dichloride (1.9 mL, 23 mmol) in dichloromethane (65 mL) at −78° C. was added a solution of dimethyl sulfoxide (3.3 mL, 47 mmol) in dichloromethane (5 mL) and the resulting solution was stirred at this temperature for 30 minutes. A solution of starting material ((3R,4S,5S)-3,4,5-tris-benzyloxy-6,6-bis-(4-methoxy-benzyloxymethyl)-tetrahydro-pyran-2-ol, (I-1d, 5.6 g, 7.7 mmol) in dichloromethane (15.0 mL) was then added dropwise and the resulting mixture was stirred for 30 minutes allowing the temperature to rise to −60° C. Triethylamine (9.7 mL, 69.5 mmol) was added dropwise and the mixture allowed to warm up to 0° C. over 1 hour. The reaction was quenched by addition of saturated aqueous ammonium chloride solution and the organic phase was dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude material was purified by flash chromatography over silica gel eluting with a gradient of 0 to 60% ethyl acetate in heptane to produce the product (I-1e) (4 g, 72% yield).

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