19706-01-5Relevant academic research and scientific papers
Organic syntheses via transition metal complexes. 78. Hydrazinolysis of alkynylcarbene complexes of chromium and tungsten. Formation of hydrazinocarbene, imidate, pyrazolidinylidene, and nitrile complexes
Aumann, Rudolf,Jasper, Beate,Fr?hlich, Roland
, p. 2447 - 2455 (2008/10/09)
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.
Organic Syntheses via Transition Metal Complexes, 55. - 5-Aza-1-metalla-1,3,5-trienes of Chromium and Tungstena and Their Cyclization to 2H-Pyrrole Complexes
Aumann, Rudolf,Heinen, Heinrich,Goddard, Richard,Krueger, Carl
, p. 2587 - 2594 (2007/10/02)
5-Aza-1-metalla-1,3,5-trienes 5 and 6 are obtained in two steps from aminocarbene complexes 1 .The first step involves the condensation of 1 with benzaldehyde (2) in the presence of TiCl4/Et3N to give 3-aza-1-metalla-1,3-dienes 3 (LnM=C-N=C). 3 adds to the 1-aminoalkyne 4 to give 5 and 6 by a chain extension of two carbon atoms.The trans isomers 5 are formed as the major products and are stable both in the solid state and in solution.The cis isomers 6 undergo a novel-type cyclization to give 2H-pyrrole complexes 8.Triene 5b was characterized by an X-ray analysis. Key Words: Aminocarbene complexes, of chromium and tungsten / 3-Aza-1-metalla-1,3-dienes, of chromium and tungsten / 5-Aza-1-metalla-1,3,5-trienes, cyclization to 2H-pyrroles / 2H-Pyrrole complexes, of chromium and tungsten / Pyrroles, syntheses by metal-induced cycloaddition reactions
Organic Syntheses via Transition Metal Complexes, 33. - 2-Azaallenyl Chromium Complexes by Condensation of Aminocarbene Chromium Complexes with Aldehydes, Acid Chlorides, or Acid Amides
Aumann, Rudolf,Althaus, Stefanie,Krueger, Carl,Betz, Peter
, p. 357 - 364 (2007/10/02)
Aminocarbene complexes LnM=C(NH2)R 1 can be converted to 2-azaallenyl complexes LnM-+=CXR1> by the condensation of the NH2 group with organic carbonyl compounds O=CYR1 in presence of Et3N and POCl3/Et3N, respectively.The condensation is achieved with a surprisingly wide variety of different carbonyl compounds like aldehydes (Y = H); acid chlorides (Y = Cl), acid amides and leads to the formation of 2-azaallenyl complexes of hitherto unknown substitution patterns 1 (7), N(CH3)2 (9)>.These have been analysed spectroscopically. 3a was characterized by an X-ray analysis. - Keywords: 2-Azaallenyl chromium complexes/ CNC building blocks/ Aminocarbene complexes
