32700-63-3Relevant academic research and scientific papers
Elucidating the Importance of Hydrochloric Acid as a Cocatalyst for Resorcinarene-Capsule-Catalyzed Reactions
K?ster, Jesper M.,Tiefenbacher, Konrad
, p. 2941 - 2944 (2018/07/29)
This survey of resorcinarene-capsule-catalyzed reactions demonstrates that HCl functions as a crucial cocatalyst by increasing the capsule's inherent Br?nsted acidity to enable or accelerate cationic reactions. The presence of HCl appears to be without consequences for other reactions.
Investigation and mechanistic study into intramolecular hydroalkoxylation of unactivated alkenols catalyzed by cationic lanthanide complexes
Zhu, Xuehua,Li, Guoyao,Xu, Fan,Zhang, Yong,Xue, Mingqiang,Shen, Qi
, p. 1451 - 1458 (2017/02/19)
Cationic lanthanide complexes of the type [Ln(CH3CN)9]3+[(AlCl4)3]3–·CH3CN (Ln = Pr, Nd, Sm, Gd, Er, Yb, Y) served as effective catalysts for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols to yield the cyclic ethers with Markovnikov regioselectivity under mild conditions. Novel cationic complexes, [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN and [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN, were synthesized and evaluated for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols for comparison. The active sequence of [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN 3CN)5]2+[(AlCl4)2]2–·CH3CN 3CN)9]3+[(AlCl4)3]3–·CH3CN observed indicated that both the cation and anion have great influence on the activity. Comparative study on the activity of AlCl3and its cationic complex [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN revealed the formation of the cationic Al center enhanced the activity greatly. The1H NMR studies indicated the activation of hydroxyl and olefin by the cationic Ln3+center were involved in the reaction pathways.
Simple salts of abundant metals (Fe, Bi, and Ti) supported on montmorillonite as efficient and recyclable catalysts for regioselective intramolecular and intermolecular hydroalkoxylation reactions of double bonds and tandem processes
Notar Francesco, Irene,Cacciuttolo, Bastien,Pascu, Oana,Aymonier, Cyril,Pucheault, Mathieu,Antoniotti, Sylvain
, p. 19807 - 19818 (2016/03/01)
The transfer of catalytic hydroalkoxylation reactions of olefins from homogeneous to heterogeneous conditions has been studied using two types of solid catalysts, namely montmorillonite (MMT) doped with metal cations and metal nanoparticles supported on oxides. In the case of intramolecular reactions, 38-99% yields of cyclic ethers have been obtained using Fe-MMT and Bi-MMT both in CH3NO2 and dimethyl carbonate (DMC) compared with other supported metal salts or metal nanoparticles. In the case of more challenging intermolecular reactions, conversions up to 72% and yields up to 54% were obtained with metal-doped MMT as well, such as Fe-, Bi-, and Ti-MMT. In this paper, we detail the substrate scope and limitations for both classes of reactions and tandem processes, their transposition in flow and some mechanistic insights concerning the active species, in processes identified as truly heterogeneously catalysed. As a general trend, it was observed that trisubstituted double bonds allowed the best results both in intra- and intermolecular reactions. The transfer of homogeneous catalysts onto heterogeneous ones in the case of Fe-MMT and Bi-MMT was successful and even allowed enhanced catalytic activities in the case of Bi-MMT.
Intramolecular hydroalkoxylation catalyzed inside a self-assembled cavity of an enzyme-like host structure
Catti,Tiefenbacher
supporting information, p. 892 - 894 (2015/02/05)
Self-assembled resorcin[4]arene hexamer catalyzes the intramolecular hydroalkoxylation of unsaturated alcohols to the corresponding cyclic ethers under mild conditions. The mode of catalysis and encapsulation-based substrate selectivity of the host efficiently mimic the basic principle of operation observed in enzymes.
Simple metal salts supported on montmorillonite as recyclable catalysts for intramolecular hydroalkoxylation of double bonds in conventional and VOC-exempt solvents
Notar Francesco, Irene,Cacciuttolo, Bastien,Pucheault, Mathieu,Antoniotti, Sylvain
supporting information, p. 837 - 841 (2015/03/04)
We describe herein an efficient and particularly sustainable catalytic system for the intramolecular hydroalkoxylation of double bonds. A heterogeneous catalyst based on the impregnation of benign metals such as iron and bismuth on montmorillonite was used for a highly atom-economic transformation in DMC, a non-VOC solvent. The transformation allowed the formation of a large range of cyclic ethers from the corresponding unsaturated alcohols and the catalyst could be recycled several times.
Intramolecular Hydroalkoxylation of Unactivated Alkenes Using Silane-Iodine Catalytic System
Fujita, Shoji,Abe, Masanori,Shibuya, Masatoshi,Yamamoto, Yoshihiko
supporting information, p. 3822 - 3825 (2015/08/18)
A novel catalytic system using I2 and PhSiH3 for the intramolecular hydroalkoxylation of unactivated alkenes is described. NMR study indicated that in situ generated PhSiH2I is a possible active catalytic species. This catalytic system allows an efficient intramolecular hydroalkoxylation of phenyl-, trialkyl-, and 1,1-dialkyl-substituted alkenes as well as a variety of unactivated monoalkyl- and 1,2-dialkyl-substituted alkenes at room temperature. Mechanistic consideration based on significant experimental observations is also discussed.
Metal-free and recyclable route to synthesize polysubstituted olefins via C-C bond construction from direct dehydrative coupling of alcohols or alkenes with alcohols catalyzed by sulfonic acid-functionalized ionic liquids
Han, Feng,Yang, Lei,Li, Zhen,Zhao, Yingwei,Xia, Chungu
, p. 2506 - 2516 (2014/09/17)
A direct synthesis of polysubstituted olefins via construction of C-C bonds, which involves the direct dehydrative coupling of alcohols or alkenes with alcohols, was realized using a series of alkanesulfonic acid group-functionalized ionic liquids (SO3H-functionlization ILs) without additives. The metal-free and recyclable catalyst system avoided the disposal and neutralization of acidic catalysts after reaction and tolerated a broad range of substrates, including benzylic, allyl, propargylic, aliphatic and aromatic or aliphatic olefins. Additionally, the catalytic system was suitable for a gram-scale preparation. Preliminary mechanistic studies indicated that the C-H bond cleavage in this reaction might be involved in the rate-determining step.
Intramolecular hydroalkoxylation of non-activated C=C bonds catalysed by zeolites: An experimental and theoretical study
Perez-Mayoral, Elena,Matos, Ines,Nachtigall, Petr,Polozij, Miroslav,Fonseca, Isabel,Vitvarova-Prochazkova, Dana,Cejka, Jiri
, p. 1021 - 1030 (2013/07/27)
The high activity and selectivity of zeolites in the cyclisation of unsaturated alcohols is reported for the first time; the details of a reaction mechanism based on quantum chemical calculations are also provided. The high efficiency of zeolites MFI, BEA and FAU in the cyclisation of unsaturated alcohols (cis-decen-1-ol, 6-methylhept-5-en-2-ol and 2-allylphenol) to afford oxygen-containing heterocyclic rings is demonstrated. The best catalytic performance is found for zeolites with the optimum concentration of Bronsted acid sites (ca. 0.2 mmol g-1) and the minimum number of Lewis acid sites. It is proposed that the efficiency of the catalysts is reduced by the existence of the so-called dual site, at which a molecule of unsaturated alcohol can simultaneously interact with two acid sites (an OH group with one and the double bond with the other Bronsted site), which increases the interaction strength. The formation of such adsorption complexes leads to a decrease in the catalyst activity because of (i) an increase in the reaction barrier, (ii) an unfavourable conformation and (iii) diffusion limitations. A new procedure for the preparation of tetrahydrofurans and pyrans over zeolite catalysts provides important oxygen-containing heterocycles with numerous applications. The zeolite fantastic: The high efficiency of zeolites MFI, BEA and FAU in the cyclisation of unsaturated alcohols to afford oxygen-containing heterocyclic rings is demonstrated. It is proposed that the efficiency of the catalysts depends on the existence of the so-called dual site, at which a molecule of an unsaturated alcohol can simultaneously interact with two acid sites. Copyright
Calcium catalyzed hydroalkoxylation
Kena Diba, Anastasie,Begouin, Jeanne-Marie,Niggemann, Meike
supporting information, p. 6629 - 6632,4 (2012/12/13)
A calcium catalyzed intramolecular hydroalkoxylation reaction is presented, as a transition metal free, inexpensive, and very mild process for the highly atom economic formation of cyclic ethers from γ,δ-unsaturated alcohols. In contrast to most of the previously reported procedures, room temperature conditions are fully sufficient in most cases for a high yielding cycloisomerization in the presence of a combination of 5 mol-% Ca(NTf 2)2 and 5 mol-% Bu4NPF6. Full regioselectivity is observed in all transformations.
Calcium catalyzed hydroalkoxylation
Kena Diba, Anastasie,Begouin, Jeanne-Marie,Niggemann, Meike
supporting information, p. 6629 - 6632 (2013/01/15)
A calcium catalyzed intramolecular hydroalkoxylation reaction is presented, as a transition metal free, inexpensive, and very mild process for the highly atom economic formation of cyclic ethers from γ,δ-unsaturated alcohols. In contrast to most of the previously reported procedures, room temperature conditions are fully sufficient in most cases for a high yielding cycloisomerization in the presence of a combination of 5 mol-% Ca(NTf 2)2 and 5 mol-% Bu4NPF6. Full regioselectivity is observed in all transformations.
