4292-92-6Relevant academic research and scientific papers
The solvent determines the product in the hydrogenation of aromatic ketones using unligated RhCl3as catalyst precursor
Bartling, Stephan,Chakrabortty, Soumyadeep,De Vries, Johannes G.,Kamer, Paul C. J.,Lund, Henrik,Müller, Bernd H.,Rockstroh, Nils
, p. 7608 - 7616 (2021/12/13)
Alkyl cyclohexanes were synthesized in high selectivity via a combined hydrogenation/hydrodeoxygenation of aromatic ketones using ligand-free RhCl3 as pre-catalyst in trifluoroethanol as solvent. The true catalyst consists of rhodium nanoparticles (Rh NPs), generated in situ during the reaction. A range of conjugated as well as non-conjugated aromatic ketones were directly hydrodeoxygenated to the corresponding saturated cyclohexane derivatives at relatively mild conditions. The solvent was found to be the determining factor to switch the selectivity of the ketone hydrogenation. Cyclohexyl alkyl-alcohols were the products using water as a solvent.
Teaching an old carbocation new tricks: Intermolecular C-H insertion reactions of vinyl cations
Popov, Stasik,Shao, Brian,Bagdasarian, Alex L.,Benton, Tyler R.,Zou, Luyi,Yang, Zhongyue,Houk,Nelson, Hosea M.
, p. 381 - 387 (2018/08/07)
Vinyl carbocations have been the subject of extensive experimental and theoretical studies over the past five decades. Despite this long history in chemistry, the utility of vinyl cations in chemical synthesis has been limited, with most reactivity studies focusing on solvolysis reactions or intramolecular processes. Here we report synthetic and mechanistic studies of vinyl cations generated through silylium-weakly coordinating anion catalysis. We find that these reactive intermediates undergo mild intermolecular carbon-carbon bond-forming reactions, including carbon-hydrogen (C-H) insertion into unactivated sp3 C-H bonds and reductive Friedel-Crafts reactions with arenes. Moreover, we conducted computational studies of these alkane C-H functionalization reactions and discovered that they proceed through nonclassical, ambimodal transition structures. This reaction manifold provides a framework for the catalytic functionalization of hydrocarbons using simple ketone derivatives.
Cross-coupling reaction of alkyl halides with alkyl grignard reagents catalyzed by cp-iron complexes in the presence of 1,3-butadiene
Iwasaki, Takanori,Shimizu, Ryohei,Imanishi, Reiko,Kuniyasu, Hitoshi,Kambe, Nobuaki
supporting information, p. 763 - 766 (2018/05/29)
Iron-catalyzed cross-coupling reaction of alkyl halides with alkyl Grignard reagents by the combined use of cyclopentadienyl ligand and 1,3-butadiene additive is described. The reaction smoothly proceeds at room temperature using unactivated alkyl bromides and fluorides via non-radical mechanism, which is in sharp contrast with hitherto known Fe-catalyzed cross-coupling reactions of alkyl halides.
Catalytic hydrogenation of aromatic rings catalyzed by Pd/NiO
Wang, Yanan,Cui, Xinjiang,Deng, Youquan,Shi, Feng
, p. 2729 - 2732 (2014/01/06)
A simple and efficient heterogeneous palladium catalyst was prepared for aromatic ring hydrogenation. The catalyst was prepared by a reduction-deposition method and exhibited high activity and selectivity for the hydrogenation of a variety of substituted aromatic compounds to the corresponding cyclohexane and cyclohexanol derivatives with up to 99% yields. The catalyst was characterized by BET, TEM, XRD, XPS and ICP. Meanwhile the reusability of the catalyst was investigated, and it can be reused for several runs without significant deactivation.
Cyclooctane metathesis catalyzed by silica-supported tungsten pentamethyl [(ΞSiO)W(Me)5]: Distribution of macrocyclic alkanes
Riache, Nassima,Callens, Emmanuel,Samantaray, Manoja K.,Kharbatia, Najeh M.,Atiqullah, Muhammad,Basset, Jean-Marie
supporting information, p. 15089 - 15094 (2015/02/19)
Metathesis of cyclic alkanes catalyzed by the new surface complex [(ΞSiO)W(Me)5] affords a wide distribution of cyclic and macrocyclic alkanes. The major products with the formula CnH2n are the result of either a ring contraction or ring expans
Copper-catalyzed alkyl-alkyl cross-coupling reactions using hydrocarbon additives: Efficiency of catalyst and roles of additives
Iwasaki, Takanori,Imanishi, Reiko,Shimizu, Ryohei,Kuniyasu, Hitoshi,Terao, Jun,Kambe, Nobuaki
, p. 8522 - 8532 (2015/01/08)
Cross-coupling of alkyl halides with alkyl Grignard reagents proceeds with extremely high TONs of up to 1230000 using a Cu/unsaturated hydrocarbon catalytic system. Alkyl fluorides, chlorides, bromides, and tosylates are all suitable electrophiles, and a TOF as high as 31200 h-1 was attained using an alkyl iodide. Side reactions of this catalytic system, i.e., reduction, dehydrohalogenation (elimination), and the homocoupling of alkyl halides, occur in the absence of additives. It appears that the reaction involves the β-hydrogen elimination of alkylcopper intermediates, giving rise to olefins and Cu-H species, and that this process triggers both side reactions and the degradation of the Cu catalyst. The formed Cu-H promotes the reduction of alkyl halides to give alkanes and Cu-X or the generation of Cu(0), probably by disproportionation, which can oxidatively add to alkyl halides to yield olefins and, in some cases, homocoupling products. Unsaturated hydrocarbon additives such as 1,3-butadiene and phenylpropyne play important roles in achieving highly efficient cross-coupling by suppressing β-hydrogen elimination, which inhibits both the degradation of the Cu catalyst and undesirable side reactions.
Copper nanoparticle-catalyzed cross-coupling of alkyl halides with Grignard reagents
Kim, Ju Hyun,Chung, Young Keun
supporting information, p. 11101 - 11103 (2013/11/19)
A cross-coupling reaction between alkyl bromides and chlorides and various Grignard reagents was carried out in the presence of commercially available copper or copper oxide nanoparticles as a catalyst and an alkyne additive. The catalytic system shows high activity, a broad scope, and good functional group tolerance.
DEHYDROGENATION OF CYCLOHEXANONE TO PRODUCE PHENOL
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Page/Page column 23; 25, (2011/09/14)
In a process for the dehydrogenation of cyclohexanone to produce phenol, a feed comprising cyclohexanone is contacted with a dehydrogenation catalyst under dehydrogenation conditions comprising a temperature of less than 4000C and a pressure of less than 690 kPa, gauge, such 0.1 to 50 wt% of the cyclohexanone in said feed is converted to phenol and the dehydrogenation product contains less than 100 ppm by weight of alkylbenzenes.
Nickel complexes of a pincer amidobis(amine) ligand: Synthesis, structure, and activity in stoichiometric and catalytic C-C bond-forming reactions of alkyl halides
Vechorkin, Oleg,Csok, Zsolt,Scopelliti, Rosario,Hu, Xile
experimental part, p. 3889 - 3899 (2009/12/26)
The synthesis, properties, and reactivity of nickel(II) complexes of a newly developed pincer amidobis(amine) ligand (McNN2) are described. Neutral or cationic complexes [(MeNN2)NiX] (X = OTf (6), OC(O)CH3 (7), CH3CN (8), OMe (9)) were prepared by salt metathesis or chloride abstraction from the previously reported [( MeNN2)NiCl] (1). The Lewis acidity of the {( McNN2)Ni) fragment was measured by the 1H NMR chemical shift of the coordinated CH3CN molecule in 8. Electrochemical measurements on 1 and 8 indicate that the electron-donating properties of NN2 are similar to those of the analogous amidobis(phosphine) (pnp) ligands. The solid-state structures of 6-8 were determined and compared to those of 1 and [(MeNN2)NiEt] (3). In all complexes, the MeNN2 ligand coordinates to the NiII ion in a mer fashion, and the square-planar coordination sphere of the metal is completed by an additional donor. The coordination chemistry of MeNN 2 thus resembles that of other three-dentate pincer ligands, for example, pnp and arylbis(amine) (ncn). Reactions of 2 with alkyl monohalides, dichlorides, and trichlorides were investigated. Selective C-C bond formation was observed in many cases. Based on these reactions, efficient Kumada-Corriu-Tamao coupling of unactivated alkyl halides and alkyl Grignard reagents with 1 as the precatalyst was developed. Good yields were obtained for the coupling of primary and secondary iodides and bromides. Double C-C coupling of CH2Cl2 with alkyl Grignard reagents by 1 was also realized. The scope and limitations of these transformations were studied. Evidence was found for a radical pathway in Ni-catalyzed C-C cross-coupling reactions, which involves NiIl alkyl intermediates.
Evidence for a NiI active species in the catalytic cross-coupling of alkyl electrophiles
Anderson, Thomas J.,Jones, Gavin D.,Vicic, David A.
, p. 8100 - 8101 (2007/10/03)
Addition of terpyridine to (TMEDA)Ni(CH3)2 results in the high-yield formation of (terpyridyl)NiMe (3). This NiI organometallic complex was found to be capable of transferring its methyl group to iodocyclohexane to produce methylcyclohexane in high yield. Compound 3 can also serve as an initiator for the catalytic cross-coupling of alkyl electrophiles performed under Negishi-like conditions. Copyright
