A novel route to 2,3-pyrazol-1(5H)-ones via palladium-catalyzed carbonylation of 1,2-diaza-1,3-butadienes.

@article{Boeckman2001ANR,
  title={A novel route to 2,3-pyrazol-1(5H)-ones via palladium-catalyzed carbonylation of 1,2-diaza-1,3-butadienes.},
  author={Robert K Boeckman and Jessica Elizabeth Reed and Peiyu Ge},
  journal={Organic letters},
  year={2001},
  volume={3 23},
  pages={
          3651-3
        }
}
[reaction--see text] A novel Pd(0)-catalyzed carbonylation of both isolable 1,2-diaza-1,3-butadienes and those generated in situ by extrusion of SO(2) and CO(2) from heterocyclic precursors is described. The reaction proceeds at room temperature to 110 degrees C under 1-2 atm of CO to afford 2,3-pyrazol-1(5H)-ones in good to excellent yields. The effect of catalyst structure and stability on the carbonylation reaction is evaluated.