Transformation of an FeP=C unit of a phosphaalkene into a FeP=C-N-N=C moiety by chain extension through insertion of the 1,3-dipole (N--N(Ar)-CH+) of sydnones

Weber L, Scheffer MH, Beckmann E-E, Stammler H-G, Neumann B. Transformation of an FeP=C unit of a phosphaalkene into a FeP=C-N-N=C moiety by chain extension through insertion of the 1,3-dipole (N--N(Ar)-CH+) of sydnones. Organometallics. 1997;16(13):2958-2962.The metallophosphaalkene (eta(5)-C5Me5)(CO)(2)FeP=C(NMe2)(2) (1) underwent reaction with sydnones 3-aryl-NNOC(O)CH (aryl = C6H5 (2a), 4-FC6H4 (2b), 4-ClC6H4 (2c), 4-BrC6H4 (2d)) to afford the novel ferriophosphaalkenes (eta(5)-C5Me5)(CO)(2)FeP=CHN(aryl)N=C(NMe2)(2) (3a-d). Compound 3a forms the [2 + 2] phosphetanyl cycloadduct 4a with dimethyl fumarate. The molecular structure of 3a was determined by single-crystal X-ray diffraction