Cleavage ammonium persulfate

The solvent-free cleavage of oximes has been successfully demonstrated (22) using relatively benign ammonium persulfate on silica (Scheme 4). Neat oximes are admixed with solid supported reagent and the contents are irradiated at full power in a MW oven to regenerate both aldehydes and ketones. The role of the solid surface is critical since the same reageit supported on a clay surface delivers predominantly the Bedonann rearrangenent products, the amides 0S). 

Water-soluble peroxide salts, such as ammonium or sodium persulfate, are the usual initiators. The initiating species is the sulfate radical anion generated from either the thermal or redox cleavage of the persulfate anion. The thermal dissociation of the persulfate anion, which is a first-order process at constant temperature (106), can be greatly accelerated by the addition of certain reducing agents or small amounts of polyvalent metal salts, or both (87). By using redox initiator systems, rapid polymerizations are possible at much lower temperatures (25—60°C) than are practical with a thermally initiated system (75—90°C). 

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