689-12-3Relevant academic research and scientific papers
Phosphine-Catalyzed Cascade Annulation of MBH Carbonates and Diazenes: Synthesis of Hexahydrocyclopenta[c]pyrazole Derivatives
Guo, Hongchao,Li, Hongxiang,Liu, Hao,Shi, Wangyu,Wang, Chang,Wang, Wei,Wu, Yongjun
supporting information, p. 5571 - 5575 (2021/07/31)
A phosphine-catalyzed cascade annulation of Morita-Baylis-Hillman (MBH) carbonates and diazenes was achieved, giving tetrahydropyrazole-fused heterocycles bearing two five-membered rings in moderate to excellent yields. The reaction underwent an unprecedented reaction mode of MBH carbonates, in which two molecules of MBH carbonates were fully merged into the ring system.
Acrylate Esters by Ethenolysis of Maleate Esters with Ru Metathesis Catalysts: an HTE and a Technoeconomic Study
Copéret, Christophe,De Jesus Silva, Jordan,Engl, Pascal S.,Fedorov, Alexey,Lange, Jean-Paul,Togni, Antonio,Tsygankov, Alexey
, (2020/04/29)
A high throughput experimentation (HTE) study identified active Ru metathesis catalysts and reaction conditions for the ethenolysis of maleate esters to the respective acrylate esters. Catalysts were tested at various loadings (75–10’000 ppm) and temperatures (30–60 °C) with maleate esters dissolved in toluene (up to ca. 44 wt-%) or neat and at variable partial pressures of ethylene (0.2–10 bar). Ruthenium catalysts containing a PCy3 ligand, such as 1st or 2nd generation Grubbs catalysts, as well as the state-of-the-art catalysts containing cyclic alkyl amino carbene (CAAC) ligands, are generally inferior to Hoveyda–Grubbs 2nd generation catalyst in ethenolysis of maleates. Productive turnover numbers could exceed 1900 if the ethenolysis reaction is performed at low ethylene pressure (0.2–3 bar) and reach 5200 when a polymeric phenol additive was used. Such catalytic performance falls well within the window practiced in industry. Moreover, a crude technoeconomic analysis finds similar production cost for the ethenolysis route and conventional technology, that is, propene oxidation followed by esterification, justifying research to further improve the ethenolysis route.
Transfer Hydrogenation of Nitriles, Olefins, and N-Heterocycles Catalyzed by an N-Heterocyclic Carbene-Supported Half-Sandwich Complex of Ruthenium
Mai, Van Hung,Nikonov, Georgii I.
, p. 943 - 949 (2016/05/09)
In the presence of KOBut, N-heterocyclic carbene-supported half-sandwich complex [Cp(IPr)Ru(pyr)2][PF6] (3) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) catalyzes transfer hydrogenation (TH) of nitriles, activated N-heterocycles, olefins, and conjugated olefins in isopropanol at the catalyst loading of 0.5%. The TH of nitriles leads to imines, produced as a result of coupling of the initially formed amines with acetone (produced from isopropanol), and showed good chemoselectivity. Reduction of N-heterocycles occurs for activated polycyclic substrates (e.g., quinoline) and takes place exclusively in the heterocycle. The TH also works well for linear and cyclic olefins but fails for trisubstituted substrates. However, the C = C bond of α,β-unsaturated esters, amides, and acids is easily reduced even for trisubstituted species, such as isovaleriates. Mechanistic studies suggest that the active species in these catalytic reactions is the trihydride Cp(IPr)RuH3 (5), which can catalyze these reactions in the absence of any base. Kinetic studies are consistent with a classical inner sphere hydride-based mechanism of TH.
Nickel-catalyzed synthesis of 1,3,5-trisubstituted hydantoins from acrylates and isocyanates
Miura, Tomoya,Mikano, Yusuke,Murakami, Masahiro
supporting information; experimental part, p. 3560 - 3563 (2011/09/16)
One molecule of acrylate reacts with two molecules of isocyanate in the presence of a nickel(0)/SIPr catalyst to give a 1,3,5-trisubstituted hydantoin. Two processes operate in sequence, the first, regioselective formation of N-substituted fumaramate from acrylate and isocyanate and, the second, ring closure of the fumaramate with incorporation of another molecule of isocyanate.
Asymmetric Diels-Alder reaction between acrylates and cyclopentadiene in the presence of chiral catalysts
Mamedov
, p. 1621 - 1625 (2008/02/07)
Asymmetric Diels-Alder reaction between cyclopentadiene and alkyl and cycloalkyl acrylates in the presence of new chiral catalysts, BBr 3?MentOEt, AlCl2OMent, BBr2OMent, and BBr(OMent)2, was studied. Optically active bicyclo[2.2.1]hept-2-ene- 5-carboxylates were synthesized. The influence of the reaction conditions on the total and optical yields and on the stereoselectivity of the adducts synthesized was examined. Nauka/Interperiodica 2006.
Synthesis of 1,4-Keto Esters and 1,4-Diketones via Palladium-Catalyzed Acylation of Siloxycyclopropanes. Synthetic and Mechanistic Studies
Fujimura, Tsutomu,Aoki, Satoshi,Nakamura, Eiichi
, p. 2809 - 2821 (2007/10/02)
The reaction of a variety of siloxycyclopropanes with acid chlorides in the presence of a catalytic amount of a palladium/phosphine complex gives 1,4-dicarbonyl compounds to good yield. 1-Alkoxy-1-(trialkylsiloxy)-cyclopropanes react with both aromatic and aliphatic acid chlorides in chloroform to give 1,4-keto esters.Synthesis of 1,4-diketones by the acylation of 1-alkyl- or 1-aryl-1-siloxycyclopropanes has been achieved by carrying out the reaction if HMPA under 10-20 atm of carbon monoxide.Kinetic studies and product analysis revealed the unique mechanism of this reaction, which involves rate-determining cleavage of the strained cyclopropane carbon-carbon bond with a coordinatively unsaturated acylpalladium chloride complex.Ab initio calculations of hydroxylated cyclopropane model compounds showed that the unique reactivities of the siloxycyclopropanes may be correlated with the molecular orbital properties of these compounds rather than their ground-state structural properties.
