Conversion of Reducing Radicals into Oxidizing Ones Umpolung

Conversion of Reducing Radicals into Oxidizing Ones (Umpolung) 

These reactions are real tautomerization reactions, but the quite common water elimination reactions can also completely change the redox property of a radical. A case in point is the radical derived from ethylene glycol which is a reducing a-hydroxyalkyl radical which is transformed by water elimination into the fomylmethyl radical (see below) whose oxidizing property has been discussed above [reaction (20)]. Similarly, the phenol OH-adduct is a reason- 

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