Organocatalytic oxidation of aldehydes to mixed anhydrides

TEMPO catalyzes the direct oxidation of aldehydes to mixed anhydrides in the presence of a carboxylic acid. The anhydrides can be converted in situ to esters, secondary, tertiary or Weinreb amides in high yield. Oxidation of the aldehyde directly to 2-propyl esters is also possible using only catalytic amounts of acid. The oxidation reactions are rapid and take place under mild conditions.