Easy and efficient synthesis of enantiomerically enriched 2H-azirines derived from phosphonates

An efficient synthesis of 2H-azirines substituted with a phosphonate group is described. The key step is an alkaloid-mediated Neber reaction of β-ketoxime tosylates. Reduction of 2H-azirines with sodium borohydride in ethanol gives 2-phosphorylated cis-aziridines.