13389-42-9Relevant articles and documents
Facile access to tuneable Schwartz's reagents: Oxidative addition products from the reaction of amide N-H bonds with reduced zirconocene complexes
Haehnel, Martin,Yim, Jacky C.-H.,Schafer, Laurel L.,Rosenthal, Uwe
, p. 11415 - 11419 (2013)
On the tracks of Schwartz's reagent: Two zirconocene hydrido amidate complexes are synthesized by formal oxidative addition of amide N-H bonds to reduced zirconocene fragments. Insertion reactions with alkenes show a different behavior than Schwartz's reagent by forming branched insertion products. The insertion product and the hydrido complex are characterized by X-ray analysis. Copyright
Catalytic isomerization and disproportionation of olefins promoted by group 4/d0 benzamidinate complexes
Averbuj, Claudia,Eisen, Moris S.
, p. 8755 - 8759 (1999)
The group 4/d0 benzamidinate complexes cis-[p-CH3-C6H4C(NSiMe3) 2]2Zr(CH3)2 (1), C3-tris([N-trimethylsilyl][N'-myrtanyl]benzamidinate)zirconium c
Highly Z-Selective Double Bond Transposition in Simple Alkenes and Allylarenes through a Spin-Accelerated Allyl Mechanism
Kim, Daniel,Pillon, Guy,Diprimio, Daniel J.,Holland, Patrick L.
, p. 3070 - 3074 (2021)
Double-bond transposition in alkenes (isomerization) offers opportunities for the synthesis of bioactive molecules, but requires high selectivity to avoid mixtures of products. Generation of Z-alkenes, which are present in many natural products and pharmaceuticals, is particularly challenging because it is usually less thermodynamically favorable than generation of the E isomers. We report a β-dialdiminate-supported, high-spin cobalt(I) complex that can convert terminal alkenes, including previously recalcitrant allylbenzenes, to Z-2-alkenes with unprecedentedly high regioselectivity and stereoselectivity. Deuterium labeling studies indicate that the catalyst operates through a π-allyl mechanism, which is different from the alkyl mechanism that is followed by other Z-selective catalysts. Computations indicate that the triplet cobalt(I) alkene complex undergoes a spin state change from the resting-state triplet to a singlet in the lowest-energy C-H activation transition state, which leads to the Z product. This suggests that this change in spin state enables the catalyst to differentiate the stereodefining barriers in this system, and more generally that spin-state changes may offer a route toward novel stereocontrol methods for first-row transition metals.
Extension of surface organometallic chemistry to metal?organic frameworks: Development of a well-defined single site [(≡Zr? O?)W(=O)(CH2TBu)3] olefin metathesis catalyst
Thiam, Zeynabou,Abou-Hamad, Edy,Dereli, Busra,Liu, Lingmei,Emwas, Abdul-Hamid,Ahmad, Rafia,Jiang, Hao,Isah, Abdulrahman Adamu,Ndiaye, Papa Birame,Taoufik, Mostafa,Han, Yu,Cavallo, Luigi,Basset, Jean-Marie,Eddaoudi, Mohamed
, p. 16690 - 16703 (2020)
We report here the first step by step anchoring of a W(≡CtBu)(CH2tBu)3 complex on a highly crystalline and mesoporous MOF, namely Zr-NU-1000, using a Surface Organometallic Chemistry (SOMC) concept and methodology. SOMC allowed us to selectively graft the complex on the Zr6 clusters and characterize the obtained single site material using state of the art experimental methods including extensive solid-state NMR techniques and HAADF-STEM imaging. Further FT?IR spectroscopy revealed the presence of a W=O moiety arising from the in situ reaction of the W≡CtBu functionality with the coordinated water coming from the 8-connected hexanuclear Zr6 clusters. All the steps leading to the final grafted molecular complex have been identified by DFT. The obtained material was tested for gas phase and liquid phase olefin metathesis and exhibited higher catalytic activity than the corresponding catalysts synthesized by different grafting methods. This contribution establishes the importance of applying SOMC to MOF chemistry to get well-defined single site catalyst on MOF inorganic secondary building units, in particular the in situ synthesis of W=O alkyl complexes from their W carbyne analogues.
Convenient Stereoselective Synthesis of the Three Isomeric 2,6-Octadienes
Walba, David M.,Wand, Michael D.,Wilkes, Martin C.
, p. 2259 - 2261 (1980)
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Nonredox Metal-Ion-Accelerated Olefin Isomerization by Palladium(II) Catalysts: Density Functional Theory (DFT) Calculations Supporting the Experimental Data
Senan, Ahmed M.,Qin, Shuhao,Zhang, Sicheng,Lou, Chenling,Chen, Zhuqi,Liao, Rong-Zhen,Yin, Guochuan
, p. 4144 - 4148 (2016)
Redox metal-ion-catalyzed olefin isomerization represents one of the important chemical processes. This work illustrates that nonredox metal ions can sharply accelerate Pd(II)-catalyzed olefin isomerization, while Pd(II) alone is very sluggish. Nuclear magnetic resonance (NMR) and ultraviolet-visible light (UV-vis) characterizations disclosed that the acceleration effect originates from the formation of heterobimetallic Pd(II) species with added nonredox metal ions, which improves the C-H activation capability of the Pd(II) moiety. Density functional theory (DFT) calculations further confirmed the sharp decrease of the energy barrier in C-H activation by the heterobimetallic Pd(II)/Al(III) species.
SYNTHESES A L'ACIDE DE SULFONES (XXIV).SYNZHESE STEREOSELECTIVE D'OLEFINES PAR HYDROGENOLISE DES VINYLSULFONES.
Bremner, John,Julia, Marc,Launay, Michele
, p. 3265 - 3266 (1982)
The now readily available E or Z vivylsulphones can be reduced stereospecifically to the corresponding olefins with sodium dithionite.
Metal-catalyzed chemical activation of calcium carbide: New way to hierarchical metal/alloy-on-carbon catalysts
Ananikov, Valentine P.,Lebedev, Andrey N.,Mironenko, Roman M.,Rodygin, Konstantin S.,Saybulina, Elina R.
, p. 281 - 289 (2022/02/23)
A simple and efficient strategy for the synthesis of “metal/alloy–on–carbon” catalysts was developed. A highly ordered extra pure graphite-like carbon material as a catalyst support was obtained after calcium carbide decomposition at 700 °C in a stream of gaseous chlorine. When Pd, Pt, Ag, Au, Co, Ni, Fe, Cu salts were added to calcium carbide prior to decomposition, a metal was reduced from a salt by elemental carbon, despite an oxidizing atmosphere. Metal particles were formed on the surface of the layered carbon material, covered with a thin layer of high–purity carbon and partially immersed in it. A catalytically active remaining metal was available for organic molecules due to the porous structure of carbon. At the same time, a metal was firmly held inside the carbon shells and was not washed out during a reaction and after washing procedures, keeping its catalytic activity unchanged for several cycles. Mixing various salts together before the reaction led to the alloys, and the ratio of the salts simply determined the ratio of the metals in the desired alloy. This approach allowed the synthesis of highly active metals/alloys on carbon catalysts with intrinsic hierarchical organization, which ensures a long-life cycle in the reaction. The obtained catalysts were successfully tested in the Suzuki-Miyaura cross-coupling reaction and showed excellent stability with a yield change less than 1% over several cycles (compared with a 64% yield decrease of commercial catalyst). The obtained catalysts have also shown very good performance in the semihydrogenation of C≡C bonds in phenylacetylene and other alkynes with selectivity up to 96% at 99% conversion.
Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
supporting information, p. 8108 - 8115 (2021/10/29)
The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
