C-C bond formation by cyanide addition to dinuclear vinyliminium complexes

The diiron vinyliminium complexes Fe₂{μ-η¹:η³-C(R′)C(H)CN(Me)(R)}(μ-CO)(CO)(Cp)₂]SO₃CF₃] (R=Me, R′ = SiMe₃ (1a); R = Me, R′ = CH₂OH (1b); R = CH₂Ph, R′ = Tol (1c), Tol = 4-MeC₆H₄; R = CH₂Ph, R′ = COOMe (1d); R = CH₂Ph, R′ = SiMe₃ (1e)) undergo regio- and stereo-selective addition by cyanide ion (from ), affording the corresponding bridging cyano-functionalized allylidene compounds Fe₂{μ-η¹:η³-C(R′)C(H)C(CN)N(Me)(R)}(μ-CO)(CO)(Cp)₂] (3a-e), in good yields. Similarly, the diiron vinyliminium complexes Fe₂{μ-η¹:η³-C(R′)C(R′)CN(Me)(R)}(μ-CO)(CO)(Cp)₂]SO₃CF₃] (R = R′ = Me (2a); R = Me, R′ = Ph (2b); R = CH₂Ph, R′ = Me (2c); R = CH₂Ph, R′ = COOMe (2d)) react with cyanide and yield Fe₂{μ-η¹:η³-C(R′)C(R′)C(CN)N(Me)(R)}(μ-CO)(CO)(Cp)₂] (9a-d). The reactions of the vinyliminium complex Fe₂{μ-η¹:η³-C(Tol)CHCN(Me)(4-C₆H₄CF₃)}(μ-CO)(CO)(Cp)₂]SO₃CF₃] (4) with NaBH₄ and afford the allylidene Fe₂{μ-C(Tol)C(H)C(H)N(Me)(C₆H₄CF₃)}(μ-CO)(CO)(Cp)₂] (5) and the cyanoallylidene Fe₂{μ-C(Tol)C(H)C(CN)N(Me)(C₆H₄CF₃)}(μ-CO)(CO)(Cp)₂] (6), respectively. Analogously, the diruthenium vinyliminium complex Ru₂{μ-η¹:η³-C(SiMe₃)CHCN(Me)(CH₂Ph)}(μ-CO)(CO)(Cp)₂]SO₃CF₃] (7) reacts with to give Ru₂{μ-η¹:η³-C(SiMe₃)CHC(CN)N(Me)(CH₂Ph)}(μ-CO)(CO)(Cp)₂] (8).Finally, cyanide addition to Fe₂{μ-η¹:η³-C(COOMe)C(COOMe)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂]SO₃CF₃] (2e) (Xyl = 2,6-Me₂C₆H₃), yields the cyano-functionalized bis-alkylidene complex Fe₂{μ-η¹:η²-C(COOMe)C(COOMe)(CN)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂] (10). The molecular structures of 3a and 9a have been elucidated by X-ray diffraction.