Reaction #87486

Reaction equation

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

Yield 72.0%

Solvents

dichloromethane

dichloromethane

dichloromethane

Conditions

Workup

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

Procedure

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).

Source