Oxaziranes fission

Oxaziranes derived from isobutyraldehyde react with ferrous salts to give only substituted formamides fEq. (23)], The chain propagating radical 30 thus suffers fission with elimination of the isopropyl group. An H-transfer would lead to substituted butyramides, which are not found. Here is seen a parallel to the fragmentation of alkoxyl radicals, where the elimination of an alkyl group is also favored over hydrogen. The formulation of the oxazirane fission by a radical mechanism is thus supported. 

The oxaziranes are in the majority of cases distillable liquids with boiling points somewhat higher than the corresponding Sehiff s bases. During distillation, temperatures above 100 C should be avoided. In distinction to the isomeric nitrones, the less polar oxaziranes are usually noncrystalline. They have a characteristic unpleasant smell and are nonbasic. Attempts to force salt formation results in fission of the three-membered ring. ... 

Fission of the Oxazirane Ring with Ferrous Salts... 

The diaziridines arc somewhat more stable than the oxaziranes. The three-membered ring of the oxaziranes is decomposed in all of its reactions, but with the diaziridines substitution on the nitrogen atoms can be effected and reactions involving fission and expansion of the ring to a five-membered ring are i)ossiblc,... 

The acid fission of the bicyclic oxazirane 14 to levulinic aldehyde [Eq. (17)]18 is a further example of a dealkylation involving a methyl shift. 

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