Straightforward access to α-carbonyloxy esters and β-keto thioethers from aryldiazoacetates.

A metal- and additive-free approach has been described for synthesizing α-carbonyloxy esters and β-keto thioethers from readily available aryldiazoacetates with carboxylic acids and thiol derivatives, respectively. α-Carbonyloxy esters and β-keto thioether derivatives were synthesized in good to high yields from aryldiazoacetates, carboxylic acids, and thiol derivatives decorated with various functional groups. Finally, the potential of the new approach is demonstrated through its application in gram-scale reactions and the synthesis of a few bioactive molecules.