117497-89-9Relevant academic research and scientific papers
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
Organische Synthesen mit Uebergangsmetall-Komplexen XLV. 3-Hydroxypyridine, 1H-Pyrrole und 2-Hydroxypyrrol-Derivate aus einem Aminocarben-Chromkomplex und Alkinen
Aumann, Rudolf,Heinen, Heinrich
, p. C1 - C6 (2007/10/02)
Pyrroles VI, 3-hydroxypyridines V and 2-hydroxypyrroles IX have been obtained from (amino,phenylcarbene)pentacarbonyl-chromium (I) by simple two-step procedures.The first step involves the generation of 2-azaallenyl(pentacarbonyl)chromium complexes III, and VIII by condensation of I with an aldehyde II and an acid chloride VII, respectively.Complexes III react with alkynes IVa-i to give pyrroles VI and 3-hydroxypyridines V.VIII adds alkynes IVa,e,g to give 2-hydroxypyrroles IX.
Thermal reactions of acyloxy and alkoxy carbene complexes with imines: Metathesis, acetate rearrangements, and a new route to imino carbene complexes via Peterson type eliminations
Murray, Christopher K.,Warner, Benjamin P.,Dragisich, Vera,Wulff, William D.,Rogers, Robin D.
, p. 3142 - 3151 (2008/10/08)
The first examples of the reactions of imines (R3N=CHR2; R3 = CH3, R2 = Ph, p-MePh) with acetoxy Fischer carbene complexes ((CO)5M=C(OAc)R1; M = Cr, W, R1 = Ph) are described. The reaction of the chromium complex gives exclusively the 0-acyl imidate 14 (MeN=C(OAc)Ph), which is the first example of a metathesis of an imine and a carbene complex. The tungsten complex gives a product that results from an unprecedented insertion of the imine into the carbene carbon-heteroatom bond along with the O-acyl imidate 14 as a minor product. This new insertion product was characterized by spectroscopic methods and by X-ray diffraction and determined to be the animal carbene complex 13b. Crystal data for 13b: space group P1, Z = 2, a = 8.269 (3) ?, b = 10.766 (5) ?, c = 13.851 (7) ?, α = 68.83 (5)°, β = 75.97 (6)°, γ = 81.39 (4)°, R = 0.046, and Rw = 0.050 for the 2267 reflections with Fo ≥ 5σ(Fo). It was determined that this insertion product is the result of an acetate transfer rather than a hydride transfer and that a likely intermediate in the mechanism is the zwitterion that results from initial addition of the imine nitrogen to the carbene carbon. The reaction of the acetoxy carbene complexes (CO)5M=C(OAc)R1 (M = Cr, W, R1 = Ph, Me, tBu) with N-trimethylsilyl imines Me3SiN=CHR2 provides a new method for the synthesis of imino carbene complexes (CO)5M=C(R1)N=CHR2 in a process that involves a Peterson type elimination. In a related reaction, it was found that imino complexes could also be accessed from the reaction of alkoxy carbene complexes (CO)5M=C(OMe)R1 (M = Cr, W, R1 = Ph, Me, tBu) with N-trimethylsilyl imines.
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
