Modified Neber rearrangement

The synthesis of optically active 3-amino-2/-/-azirines was carried out using a modified Neber rearrangement in the laboratory of I.P. Piskunova. The optically active amidoximes were acylated using mesyl chloride to give 0-mesyl derivatives that upon treatment with sodium methoxide afforded the desired product with high diastereoselectivity. 

The Neber rearrangement of oxime 0-sulfonates to 2//-azirines (or a-amino ketones, after aqueous acid workup) has been reviewed, together with the modified Neber , involving /V,/V,A-trimethylhydrazonium iodides.With an excess of base, the a-amino acetal can be formed from the 2//-azirine via the unstable 2-alkoxy aziridine. 

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