A direct conversion of carboxylic acids to methylthiomethyl esters using a microwave-assisted pummerer rearrangement with dimethylsulfoxide

A simple microwave-assisted method for the conversion of carboxylic acids to MTM esters is presented. This new process allows for rapid introduction of an MTM ester protecting group to a variety of carboxylic acids including alkyl, electron-rich aromatic, and long chain unsaturated carboxylic acids. The products isolated from this reaction are very pure after a simple extraction, which eliminates the need for further purification. The reaction has also been carried out on 1.50 g without deterioration of product yields or purity.