First introduced in 1995 by Herrmann into the field of Pd-catalyzed cross-coupling reactions, N-heterocyclic carbenes (NHCs) have become a paradigmatically new generation of strong ¦" donor ligands and widely used in transition metal catalysis, as exemplified by the development of highly reactive catalysts for olefin metathesis and for room-temperature Suzuki coupling involving aryl chlorides. Electronic and skeletal variation on the original Arduengo carbene has led to the discovery of a number of diaminocarbene ligands. Compared to cyclic diaminocarbenes and other heterocyclic carbenes, nucleophilic carbocyclic carbenes are much less well known. We were intrigued by the possibility of a six-membered anionic aromatic carbene ligand. Such a carbene would represent an otherwise rarely considered resonance of a phenyl anion. Toward this goal, nitrones derived from aromatic aldehydes were used as the ligand precursors. The resulting air and moisture stable palladium complexes exhibit unprecedented high catalytic efficiency in the Heck reaction. Deactivated aryl bromides such as 4-bromoanisole undergo coupling with styrene in the presence of 8 x 10^-5 mol % of the catalysts with TON exceeding 0.9 million.