Novel Iodocyclization Method Based on the Controlling of Oxidative Aromatization

We have developed a new method of iodocyclization based on reagent-controlled oxidative aromatization. Our strategy takes advantage of the dual nature of iodine as both an iodinating and an oxidizing agent. This approach enabled "product switch" and enhanced the flexibility of the synthetic pathway toward pyrazoles and isoxazoles. In addition, the iodo moiety of the cyclized product could create further diversity. The utility of our methodology was demonstrated in the synthesis of valdecoxib and its 2,5-dihydro analogs.