20001-59-6Relevant academic research and scientific papers
Palladium-Catalyzed Alkoxycarbonylation of sec-Benzylic Ethers
Beller, Matthias,Jackstell, Ralf,Maes, Bert U. W.,Schneider, Carolin
supporting information, (2020/02/25)
Herein, we report the palladium-catalyzed synthesis of 3-arylpropionate esters starting from secondary benzylic ethers. With this investigation it could be shown that ethers are suitable starting materials in addition to the established carbonylation reactions of olefins, alcohols, or aryl halides.
Redox-Switchable Hydroelementation of a Cobalt Complex Supported by a Ferrocene-Based Ligand
Shepard, Scott M.,Diaconescu, Paula L.
, p. 2446 - 2453 (2016/08/16)
The first crystallographically characterized tetrahedral cobalt salen (salen = N,N′-ethylenesalicylimine) complex was synthesized by using a 1,1′-ferrocene derivative, salfen (salfen = 1,1′- di(2,4-di-tert-butyl-6-salicylimine)ferrocene). The complex undergoes two oxidation events at low potentials, which were assigned as ligand centered by comparison to the corresponding zinc complex. The cobalt complex was found to catalyze the hydroalkoxylation of styrenes, similarly to related square planar cobalt salen complexes, likely due to its fluxional behavior in alcoholic solvents. Furthermore, the one-electron-oxidized species was found to be inactive toward hydroalkoxylation. Thus, the hydroalkoxylation reactivity could be turned on/off in situ by redox chemistry.
Hydroalkoxylation of unactivated olefins with carbon radicals and carbocation species as key intermediates
Shigehisa, Hiroki,Aoki, Tatsuya,Yamaguchi, Sumiko,Shimizu, Nao,Hiroya, Kou
supporting information, p. 10306 - 10309 (2013/08/23)
A unique Markovnikov hydroalkoxylation of unactivated olefins with a cobalt complex, silane, and N-fluoropyridinium salt is reported. Further optimization of reaction conditions yielded high functional group tolerance and versatility of alcoholic solvent employed, including methanol, i-propanol, and t-butanol. Use of trifluorotoluene as a solvent made the use of alcohol in stoichiometric amount possible. Mechanistic insight into this novel catalytic system is also discussed. Experimental results suggest that catalysis involves both carbon radical and carbocation intermediates.
Catalytic hydroalkoxylation of alkenes by iron(III) catalyst
Ke, Fang,Li, Zhengkai,Xiang, Haifeng,Zhou, Xiangge
supporting information; experimental part, p. 318 - 320 (2011/02/26)
Catalytic hydroalkoxylation of alkenes by iron(III) chloride in the presence of toluenesulfonic acid (TsOH) was developed in moderate to good yields up to 91%. Intramolecular cyclization of 5-hydroxyl pentene afforded 2-methyltetrahedronfuran in 63% yield.
Efficient addition of alcohols, amines and phenol to unactivated alkenes by AuIII or PdII stabilized by CuCl2
Zhang, Xin,Corma, Avelino
, p. 397 - 403 (2008/09/17)
The nucleophilic addition of alcohols, amines and phenol to unactivated alkenes catalyzed by cationic gold and palladium becomes limited due to the fast reduction into metallic gold under reaction conditions. The presence of CuCl2 retards the reduction of AuIII and PdII, strongly increasing the turnover number of gold and palladium catalysts. It is shown that new AuIII-CuCl2 and PdII-CuCl 2 catalysts are active and selective for the nucleophilic addition of alcohols, amines and phenol to unactivated alkenes. This journal is The Royal Society of Chemistry.
Effective Au(III)-CuCl2-catalyzed addition of alcohols to alkenes
Zhang, Xin,Corma, Avelino
, p. 3080 - 3082 (2008/02/10)
Alkenes can be activated by Au(III) catalysts, and the effective addition of alcohols to alkenes can be carried out under mild conditions with Au(III), provided that catalytic amounts of CuCl2 are added, which significantly stabilize the cationic Au(III). The Royal Society of Chemistry.
Palladium-catalyzed hydroesterification of styrene derivatives in the presence of ionic liquids
Klingshirn, Marc A.,Rogers, Robin D.,Shaughnessy, Kevin H.
, p. 3620 - 3626 (2007/10/03)
The palladium-catalyzed hydroesterification of olefins occurs efficiently in a range of ionic liquid media. Selectivities ranging from 5-7:1 for the linear ester were obtained with styrene in a range of IL solvents. The use of ILs allowed the catalyst to be easily separated from the organic product by either extraction or distillation. The (Ph3P)2PdCl 2 precatalyst could be recovered unchanged from the ionic liquid phase. The IL/catalyst phase could be recycled five times with an average yield of 68%.
Tri-n-butylstannyl chloride-sodium cyanoborohydride mediated regioselective reductive demethoxylation of alkyl methyl ketals
Srikrishna,Viswajanani
, p. 621 - 625 (2007/10/03)
A regioselective reductive demethoxylation of alkyl methyl ketals employing sodium cyanoborohydride in the presence of a catalytic amount of tri-n-butyltin chloride as Lewis acid is described.
The Mechanism of RuO4-Mediated Oxidations of Ethers: Isotope Effects, Solvent Effects and Substituent Effects
Bakke, Jan M.,Froehaug, Astrid E.
, p. 615 - 622 (2007/10/02)
The mechanism of the RuO4-mediated oxidation of ethers to esters has been investigated.Oxidation of cyclopropylmethyl methyl ether gave methyl cyclopropanecarboxylate.No rearranged products were observed.On RuO4 oxidation of benzyl methyl ether and p-methoxybenzyl methyl ether in CCl4 with NaIO4 as stoichiometric oxidant, no chlorinated products were observed.A series of 4-substituted benzyl methyl ethers was oxidized with RuO4-NaIO4.A correlation of the rate of the reaction with Hammett ?-values gave a ρ of -1.7, indicating only a moderate charge separation in the transition state (TS).Benzyl methyl ether (1) was oxidized in a series of acetone-water mixtures.From these experiments, a Grunwald-Winstein m-value of 0.11 was obtained, indicating a non-polar TS for the reaction.PhCHDOCH3 (2) and PhCD2OCH3 (3) were oxidized and two deuterium isotipe effects, one of 6.1+/-0.4 and another of 1.3+/-0.1 were obtained.If one assumes a one-step reaction mechanism, the value of 1.3 would be a large α-secondary isotope effect, indicating a change in the hybridization of the benzylic carbon during the reaction. α-Methylbenzyl methyl ether (4) was oxidized at a seventh of the rate of 1, despite the fact that 4 would have given a more stable carbocation than 1.These conflicting pieces of evidence are difficult to rationalise with a hydride or hydrogen abstraction mechanism.Instead it is proposed that the reaction proceeds by either a concerted reaction or by a reversible oxidative addition of the ether to RuO4 followed by a slow concerted step to give the product.
A mild and simple procedure for the reductive cleavage of acetals and ketals
Srikrishna, Adusumilli,Viswajanani, Ranganathan
, p. 3339 - 3344 (2007/10/02)
A convenient, mild and simple procedure, employing sodium cyanoborohydride in the presence of either catalytic or stoichiometric amount of boron trifluoride etherate in dry THF, for the reductive cleavage of the acetals and ketals is described.
