Chromium trichloride catalyst

A solution of the step 1 product (3.85 mmol) dissolved in 40 ml of THF was added to a suspension of potassium hydride (3.85 mmol) in 20 ml of THF and then stirred at ambient temperature for 6 hours. This was then added to a solution of chromium trichloride tris(THF) (3.85 mmol) dissolved in 50 ml of THF. The mixture was stirred at ambient temperature for 12 hours, concentrated, and the residue washed three times with hexane and three times with toluene. The soluble components were dissolved in CH2CI2 and the solution filtered. The filtrate was concentrated, dried under reduced pressure, and 0.969 g of the catalyst isolated. 

Transition metal catalysts not only increase the reaction rate but may also affect the outcome of the oxidation, especially the stereochemistry of the products. Whereas hydrogen peroxide alone in acetonitrile oxidizes alkenes to epoxides [729], osmic acid catalyzes syn hydroxylation [736], and tungstic acid catalyzes anti hydroxylation [737]. The most frequently used catalysts are titanium trichloride [732], vanadium pentoxide [733,134], sodium vanadate [735], selenium dioxide [725], chromium trioxide [134], ammonium molybdate [736], tungsten trioxide [737], tungstic acid [737],... 

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