1- Allyl-3,5-dimethylpyrazole, reaction with

With the advent of the chromium trioxide-3,5-dimethylpyrazole complex as an oxidant - allylic oxidation has become far more valuable as a synthetic transfonnation. The reagent was applied by Sala-mond to the allylic oxidation of cholesteryl benzoate to give the correspondbg A -7-ketone (equation 35). However, a 20 molar excess of reagent was still requii to effect the reaction in less than 30 min at room temperature. 

Two independent syntheses of quadrone eiiq>loyed an allylic oxidation with rearrangement, as shown in equation (3), where the chromium trioxide-(3,5-dimethylpyrazole) reagent (CrOs DMP) was used. In some cases, the success of the reaction strongly depends on the nature of the oxidant, as shown in an iq>proach to (-)-upial (equation 4). Here the chi ium trioxide-heterocycle reagents, which are weaker oxidants, are quite inferior compared to the Fieser reagent ... 

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