The oxirane is first converted into a 2-azidoalcohol with the use of an
azide such as
sodium azide. The azido alcohol is then reduced with the use of a trialkylphosphine such as
triphenylphosphine in a manner similar to the
Staudinger reaction, concomitant with loss of N2. The resulting
phosphanimine (formerly called iminophosphorane) intermediate is then attacked by the alcohol, with oxygen forming a bond with the phosphorus atom. Forming a ring intermediate. After a proton transfer, a pair of electrons from the oxygen atom shifts onto the phosphorus atom, and the phosphorus-nitrogen bond breaks, with the electron pair shifting onto the nitrogen atom. The negatively charged nitrogen atom attacks the carbon atom that the oxygen atom is connected to. This gives us our desired aziridine and a trialkylphosphine oxide as a side product. ==Applications==