Reaction #64080

Reaction equation

sodium hydrogen carbonate

(3R)-2-methyl-3-hydroxybutanoic acid

chloral

pyridinium p-toluenesulfonate

→

(2R, 6R)-2-trichloromethyl-5,6-dimethyl-1,3-dioxan-4-one

Yield 83.5%

Solvents

dichloromethane

Conditions

Workup

1. 1
   Temperaturewas refluxed for 25 hours under a dehydration condition
2. 2
   Otherthe resulting separated organic phase
3. 3
   Dryingwas dried over anhydrous magnesium sulfate
4. 4
   workup.DISTILLATIONthe solvent was distilled off

Procedure

A mixture of (3R)-2-methyl-3-hydroxybutanoic acid 3.6 g, chloral 8.3 g, pyridinium p-toluenesulfonate (PPTS) 0.7 g and dichloromethane 20 ml was refluxed for 25 hours under a dehydration condition. 40 ml of a saturated aqueous sodium hydrogen carbonate was added thereto and the resulting separated organic phase was dried over anhydrous magnesium sulfate and the solvent was distilled off to obtain 6.3 g of (2R, 6R)-2-trichloromethyl-5,6-dimethyl-1,3-dioxan-4-one.

Source