From Oxaziridines

Cleavage of N—N by potassium f-butoxide to give amidine (164) was observed with diaziridine (134). This is the only known analog of the generally observed acid amide formation from oxaziridines (74JPR999). 

Aliphatic nitroso compounds are obtained either by hypobromite oxidation of alkylhy-droxylamines made by oxaziridine hydrolysis, or directly from oxaziridines by action of a second mole of peracid (Section 5.08.3.1.3). 

Three preparations of 1-azetine iV-oxides have been reported. Oxidation of the 2-aryl-l-azetine (222) with MCPBA gives the nitrone (223) (79CB3914>. However, similar treatment of 2-alkoxy-l-azetines fails to give the corresponding iV-oxides but yields products derived from oxaziridines (cf. Section 5.09.4.2.3). 

Some 3,5-diarylisoxazolidines were prepared hy [3+2]-cycloaddition of C-aryloxaziridines with vinyl aromatic compounds. For example, isoxazolidine 82 was obtained in high yield from oxaziridine 81 and l-methyl-4-vinylbenzene in refluxing toluene. The stereoselectivity of the reaction was greatly affected by the nature of the substituents on the reagents, and in some cases mixtures of cis- and trans-adducts were formed. Experimental data suggested that oxaziridines react directly with alkenes without the intermediate formation of the isomeric nitrones <07T12896>. 

Yield of allenes 47a-e from sulfides unbranched in a-position to sulfur are moderate to high. However, a-branching to sulfur lead to lower yields (allenes 47f-h) and is accompanied by competing formation of sulfoxides by 0-transfer from oxaziridine 44. The metal-free reaction conditions allow synthesis of particularly sensitive allenes or those derived from sensitive sulfides... 

The mechanism of oxygen transfer from oxaziridines to nucleophiles is believed to involve an Sn2 type reaction and this assumption is supported by theoretical and experimental studies. When sulfides are oxidized to the corresponding sulfoxides and sulfones, the molecular recognition is steric in origin, and it is determined by the substituents on both the substrate and the oxaziridine. For the oxidation of enolates, the molecular recognition is explained with an Sn2 mechanism as well as by an open (non-chelated) transition state where the nonbonded interactions are minimized. The mechanism of oxygen transfer to an enolate to form the corresponding acyloin is shown below. ... 

Bach, R. D., Wolber, G. J. Mechanism of oxygen transfer from oxaziridine to ethylene the consequences of HOMO-HOMO interactions on frontier orbital narrowing. J. Am. Chem. Soc. 1984,106,1410-1415. 

Bach, R. D., Andres, J. L., Davis, F. A. Mechanism of oxygen atom transfer from oxaziridine to a lithium enolate. A theoretical study. J. Org. Chem. 1992, 57, 613-618. 

Sulfur-containing heterocumulenes react with rupture of the N—O bond of the oxaziridine. Carbon disulfide reacts at its boiling temperature to form, e.g., methyl isothiocyanate from oxaziridine 23. Extrusion of sulfur, plausible from an intermediate like 24, was observed. 

Homolytic cleavage of oxaziridines by ferrous salts, already described by Emmons, is a useful source of alkyl radicals. From oxaziridine 28, easily accessible from cyclohexanone and Af-chloromethylamine, on the action of ferrous salt, reaction products of radical 29 are obtained In the presence of FeCl2 oj-chlorohexanoic acid methylamide (30) is formed quantitatively in the absence of reaction partners, dimerization occurs to 31. As shown in a very careful investigation by Hawkins in the case of the N-cyclohexyl compound, the dicarboxylic acid derivative is accompanied by appreciable quantities of branched-acid derivatives, formed by a radical rearrangement 29 -> 32. The radical 29 adds to pyridine and gives rise, after rearomatization, to the formation of 70-80% of 2- and 4-substituted pyridine (33). ... 

Scheme 6.12 Photochemical generation of nitrenes from oxaziridines. 6.3.5...

Without additional reagents Cyclic nitrones from oxaziridine ring and reverse isomerization... 

From oxaziridines. The reaction of oxaziridines (51) with phenyl isothiocyanate yields carbodi-imides, but, under mild conditions, produces considerable amounts of the 1,2,4-thiadiazolidines (53a) and/or (53b). The reactions are likely to proceed by reaction paths outlined in Scheme 2, involving the intermediate... 

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