Synthesis of Aziridine- and Oxirane-2-phosphonates Spiro-Fused with Oxindoles

3-(Phosphorylmethylene)oxindoles have been prepared by a straightforward Horner-Wadsworth-Emmons reaction. They were treated with ethyl N-{[(4-nitrophenyl)sulfonyl]oxy}-carbamate (NsONHCO(2)Et) in the presence of CaO to afford new aziridine-2-phosphonates spiro-fused with oxindole. 3(Phosphorylmethylene)oxindoles were also transformed into novel spiro[oxindole-oxiranes] by reaction with H2O2/NaOH.