Substrates for nucleophilic substitution reactions are characterized by the presence of leaving groups. Leaving groups are substituents which are able to leave as a stable, weakly basic species. In some cases, leaving groups leave as anions, in other they leave as neutral molecules.
| Relative Reactivity | Leaving Group |
|---|---|
| Excellent | Tosylate(TsO-), Water(H2O), Ammonia(NH3) |
| Very Good | Iodide(I-) |
| Good | Bromide(Br-) |
| Fair | Chloride(Cl-) |
| Poor | Fluoride(F-) |
| Almost Unreactive | Hydroxide(HO-), Amide(NH2-), Alkoxide(RO-) |
Last modified May 16, 1996
Abby Parrill and Dr. Jacquelyn Gervay
The Department of Chemistry
The University of Arizona
Tucson, AZ 85721
Please contact Abby Parrill at abby@mercury.aichem.arizona.edu with problems and comments.