Azidation of beta-Keto Esters and Silyl Enol Ethers with a Benziodoxole Reagent

The efficient azidation of beta-keto esters and silyl enol ethers using a benziodoxole-derived azide transfer reagent is reported. The azidation of cyclic beta-keto esters could be achieved in up to quantitative yields in the absence of any catalyst. In the case of less reactive linear beta-keto esters and silyl enol ethers, complete conversion and good yields could be obtained by using a zinc catalyst.