Oxaziridines ring-opening reactions

The outcome of this reaction can be rationalized by oxygen transfer from a transient intermediate (118 or an oxaziridine) to 1,3-DIBF [but see 89H(29)263]. Trapping of acylnitroso compounds yields similar products [81 JCS(P1)3250]. A similar ring-opening reaction has been observed when diarylalkylidencyclopropenes were reacted with 1,3-DIBF (93TL3131). Without citing [89H(29)263] C Moinet and co-workers reported a... 

Cu(I)-Cu(II) Catalysis Radical Reactions Triggered by Oxaziridine Ring Opening... 

In a variant of this type of reaction in the diazepine system, the oxaziridine ring-opening was followed by reaction of the iminal that led to the destruction of the heterocyclic ring ... 

Fig. 71 Radical reactions triggered by reductive ring opening of oxaziridines...

However, more complex sulfur nucleophiles, such as thiourea, thiocyanate ion, and xanthate salts appeared to accomplish deoxygenation of the oxaziridines by ring-opening attack at carbon followed by the usual reactions leading to thia-ziridines, which lost elemental sulfur." ... 

In the photolysis of 4,6-diphenylpyridine 1-oxide, both ring-expansion and ring-contraction products were obtained and the proposed oxaziridine intermediate could be detected. Other reactions also give evidence of oxaziridines. Although there seems to be some growing acceptance of the intermediacy of oxaziridines in these reactions, it has recently been suggested that even these more recent studies can be rationalized better by open intermediates (biradicals) rather than by oxaziridine formation. ... 

The mechanisms of these reactions are highly speculative because several steps must be involved, but it can generally be said that the Japanese workers propose a scheme similar to that of Hata and Watanabe for reactions of oxaziridines with nucleophiles, in which the transition state for the initial reaction has a nitrenoid character and leads to an ylide intermediate. On the other hand, Abou-Gharbia and Joullie propose cycloaddition of a zwitterionic ring-opened oxaziridine leading to a heterocycle that subsequently decomposes. 

The oxidative deamination of amines to ketones, via oxaziridines, was reported as a model for the process found in oxidative deamination of a-amino-acids to pyruvic acids in biochemical systems." The primary amine, such as (58) or (59) with pyridine-2-carboxaldehyde, was converted into the imine (60) which was oxidized with m-chloroperbenzoic acid to the oxaziridine (61). Ring opening of (61) was effected with KOH in MeOH or in DMF (Scheme 8). Acetone was added to trap regenerated pyridine-2-carboxaldehyde. When other bases were used a competing reaction resulting in (62) occurred. 

Almost exclusively the reactions of oxaziridines involve ring opening with all of the various combinations of C—O, C—N and N—O bond cleavage having been reported. Which bond is... 

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