23183-11-1Relevant articles and documents
Aromatic compound hydrogenation and hydrodeoxygenation method and application thereof
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Paragraph 0094-0096; 0098; 0100-0104, (2021/05/29)
The invention belongs to the technical field of medicines, and discloses an aromatic compound hydrogenation and hydrodeoxygenation method under mild conditions and application of the method in hydrogenation and hydrodeoxygenation reactions of the aromatic compounds and related mixtures. Specifically, the method comprises the following steps: contacting the aromatic compound or a mixture containing the aromatic compound with a catalyst and hydrogen with proper pressure in a solvent under a proper temperature condition, and reacting the hydrogen, the solvent and the aromatic compound under the action of the catalyst to obtain a corresponding hydrogenation product or/and a hydrodeoxygenation product without an oxygen-containing substituent group. The invention also discloses specific implementation conditions of the method and an aromatic compound structure type applicable to the method. The hydrogenation and hydrodeoxygenation reaction method used in the invention has the advantages of mild reaction conditions, high hydrodeoxygenation efficiency, wide substrate applicability, convenient post-treatment, and good laboratory and industrial application prospects.
A structure-activity study of Ni-catalyzed alkyl-alkyl kumada coupling. Improved catalysts for coupling of secondary alkyl halides
Ren, Peng,Vechorkin, Oleg,Von Allmen, Kim,Scopelliti, Rosario,Hu, Xile
supporting information; experimental part, p. 7084 - 7095 (2011/06/26)
A structureactivity study was carried out for Ni catalyzed alkylalkyl Kumada-type cross coupling reactions. A series of new nickel(II) complexes including those with tridentate pincer bis(amino)amide ligands (RN2N) and those with bidentate mixed amino-amide ligands (RNN) were synthesized and structurally characterized. The coordination geometries of these complexes range from square planar, tetrahedral, to square pyramidal. The complexes had been examined as precatalysts for cross coupling of nonactivated alkyl halides, particularly secondary alkyl iodides, with alkyl Grignard reagents. Comparison was made to the results obtained with the previously reported Ni pincer complex [( MeN2N)NiCl]. A transmetalation site in the precatalysts is necessary for the catalysis. The coordination geometries and spin-states of the precatalysts have a small or no influence. The work led to the discovery of several well-defined Ni catalysts that are significantly more active and efficient than the pincer complex [(MeN2N)NiCl] for the coupling of secondary alkyl halides. The best two catalysts are [(HNN)Ni(PPh3)Cl] and [(HNN)Ni(2,4-lutidine)Cl]. The improved activity and efficiency was attributed to the fact that phosphine and lutidine ligands in these complexes can dissociate from the Ni center during catalysis. The activation of alkyl halides was shown to proceed via a radical mechanism.
The Mechanim of Formation of Grignard Reagents: Trapping of Free Alkyl Radical Intermediates by Reaction with Tetramethylpiperidine-N-oxyl
Root, Karen S.,Hill, Craig L.,Lawrence, Lynette M.,Whitesides, George M.
, p. 5405 - 5412 (2007/10/02)
In the presence of the free radical scavenger 2,2,6,6-tetramethylpiperidine-N-oxyl (TMPO., 0.50 M), cycloheptyl bromide (RBr, 0.001 M) reacts with magnesium metal in a solution containing tert-amyl alcohol (5.0 M), lithium bromide (0.05 M), and diethyl ether at 20 deg C and forms N-cycloheptoxy-2,2,6,6-tetramethylpiperidine (TMPOR) as the major product (>/=93percent yield, based on RBr).In the absence of TMPO., cycloheptane (RH) is formed in >/=95percent yield.The dependence of the relative yields of TMPOR and RH on the initial concentration of TMPO. suggests that bothproducts share a common precursor-free cycloheptyl radical-and that this radical has a median lifetime of ca. 1E-7 s.Cycloheptyl radicals appear to be intermediates on the major path to the Grignard reagent cycloheptylmagnesium bromide.TMPO. is reduced by Mg(0) to the anion of the corresponding hydroxylamine, TMPO(1-), at a rate that is competitive with that of the reaction between RBr and Mg(0).Although the magnesium salts of TMPO(1-) are insoluble in diethyl ether, solutions containing TMPO(1-), Mg(2+), and Li(1+) remain homogeneous.For systems containing a high concentration of tert-amyl alcohol, a simple mathematical model attributes apparent zero-order kinetic behavior to the dependence of reactive surface area on the extent of reaction between alkyl halide and Mg.
