Organic syntheses via transition metal complexes. 78. Hydrazinolysis of alkynylcarbene complexes of chromium and tungsten. Formation of hydrazinocarbene, imidate, pyrazolidinylidene, and nitrile complexes

Article abstract of DOI:10.1021/om00005a048

Hydrazinolysis of alkynylcarbene complexes (CO)₅M=C(OEt)C≡Ph (1, M = W; 1′, M = Cr) with mono- and 1,2-dimethylhydrazine MeHNNHR (2a,b) (R = Me, H) affords three different-type compounds: hydrazinocarbene complexes (CO)₅M=C(NMe-NHR)C≡CPh [(E/ Z)-3a,b], imidate complexes (CO)₅M[MeN=C(OEt)-C≡CPh] [(E/Z)-4a], and pyrazolidinylidene complexes 5a,b. Hydrazinolysis of 1/1′ with 1,1-dimethylhydrazine or (unsubstituted) hydrazine H₂NNR₂ (2c,d) (R = Me, H) yields hydrazinocarbene complexes (CO)₅M=C(NH-NR₂)C≡CPh [(E/Z)-3c], imidate complexes (CO)₅M[HN=C(OEt)C≡CPh] [(E/Z)-4a], and benzonitrile complexes (CO)₅M(N≡CPh) (8). Hydrazinolysis of 1 with H₂NNHR (2e,f) (R = COMe, Ph) gives pyrazoles 12e,f as the only products. The product composition of the reactions of 2a-d with 1 is markedly influenced by the reaction temperature. Reaction of 1 with N- and O-methylhydroxylamines (13, 14) affords imidate complexes 4 only. The hydrazinocarbene complexes (E)-3a and (Z)-3c were characterized by X-ray diffraction. Both compounds crystallize in space group P1 (No. 2): (E)-3a, C₁₆H₁₂N₂O₅W, cell parameters a = 8.501(2) ?, b = 9.645(2) ? c = 11.860(2) ?, α = 103.56(2)°, β = 95.59(2)°, γ = 111.76(2)°, Z = 2, R₁ = 0.043, and wR² = 0.083; (Z)-3c, C₁₆H₁₂N₂O₅W, cell parameters a = 9.380(3) ?, b = 9.685(4) ?, c = 10.804(3) ?, α = 84.77(5)°, β = 80.74(3)°, γ = 66.47(3)°, Z = 2, R₁ = 0.036, and wR² = 0.086.