Decarboxylative radical azidation using MPDOC and MMDOC esters.

An efficient radical-mediated decarboxylative azidation of aliphatic carboxylic acids has been developed. The success of this transformation hinges on the use of a new type of thiohydroxamate esters (MPDOC esters). These esters are more stable than the classical Barton esters and less prone to rearrange under radical conditions. In the case of alpha-alkoxy and alpha-amino acids, optimal results are obtained with the even more stable MMDOC esters developed recently by Kim.