Syn addition is the addition of two substituents to the same side (or face) of adouble bond or triple bond, resulting in a decrease in bond order but an increase in number of substituents. Generally the substrate will be an alkene or alkyne. An example of syn addition would be the oxidation of an alkene to a diol via a suitable oxidizing agent such asOsmium tetroxide OsO4 or Potassium permanganate KMnO4.
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