Construction of Multi‐Substituted Benzenes via NHC‐Catalyzed Reactions of Carboxylic Esters

A carbene‐catalyzed ester activation reaction for the synthesis of multi‐substituted benzenes is developed. Tetra‐substituted benzene compounds are efficiently synthesized through this methodology. Compared with aldehyde substrates used in previous reports, the ester substrates used here are much more readily available and inexpensive. In addition, the TEMPO oxidant used here is more inexpensive than the quinones commonly used in related carbene‐catalyzed reactions.