- Iridium-catalyzed enantioselective intramolecular hydroarylation of allylic aryl ethers devoid of a directing group on the aryl group
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Although intramolecular hydroarylation is an attractive transformation of allylic aryl ethers, it has suffered from narrow substrate scope. We herein describe Ir/(S)-DTBM-SEGPHOS-catalyzed intramolecular hydroarylation of allylic aryl ethers. The reaction
- Kusaka, Satoshi,Ohmura, Toshimichi,Suginome, Michinori
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p. 13542 - 13545
(2021/12/23)
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- One simple Ir/hydrosilane catalytic system for chemoselective isomerization of 2-substituted allylic ethers
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Here, we describe one simple Ir/hydrosilane catalytic system for chemoselective isomerization of 2-substituted allylic ethers. This facile strategy shows high efficiency towards a variety of substrates, including derivatives from bioactive molecules. The
- Gao, Weiwei,Zhang, Xueyan,Xie, Xingze,Ding, Shengtao
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supporting information
p. 2012 - 2015
(2020/02/22)
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- Lewis acid promoted double bond migration in O-allyl to Z-products by Ru-H complexes
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In catalytic double bond migration reaction, E-configuration olefins were normally generated as the dominant product because E-configuration was thermodynamically favored. However, Z-configuration products are sometimes desired in pharmaceutical chemistry owing to the structure-activity relationship. In this paper, we have demonstrated a new strategy that Lewis acid promoted an widely employed and convenient ruthenium(II) complex for the catalytic isomerization of O-allylethers, leading to thermodynamic-unfavored Z-product under mild conditions. The model substrate of allyl phenyl ether can be simply scaled up to 20 mmol to produce Z-product with TON of 2453 and TOF of 13,430 h?1 at 40–60 °C. The system of Ru(II)/Lewis Acid catalysts was suitable for various substituted O-allylethers and other types of substrates. Through mechanism study including kinetic study, ligand inhibition effect and molecular spectroscopy, the dissociation of PPh3 ligand by the addition of Lewis acid, and the formation a five-membered Ru complex from anchimeric assistance were both recognized as essential steps to improve the reactivity and to control the stereoselectivity of catalytic double bond migration reaction through metal hydride addition-elimination mechanism. This new strategy may provide a new opportunity to produce thermodynamic-unfavored product in heterocyclic compounds for pharmaceutical chemistry.
- Wang, Haibin,Liu, Shaodong,Sun, Tingting,Lv, Zhanao,Zhan, Zhen,Yin, Guochuan,Chen, Zhuqi
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- Stereoselective alkene isomerization over one position
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Although controlling both the position of the double bond and E:Z selectivity in alkene isomerization is difficult, 1 is a very efficient catalyst for selective mono-isomerization of a variety of multifunctional alkenes to afford >99.5% E-products. Many reactions are complete within 10 min at room temperature. Even sensitive enols and enamides susceptible to further reaction can be generated. Catalyst loadings in the 0.01-0.1 mol% range can be employed. E-to-Z isomerization of the product from diallyl ether was only -6 times as fast as its formation, showing the extremely high kinetic selectivity of 1.
- Larsen, Casey R.,Grotjahn, Douglas B.
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supporting information; experimental part
p. 10357 - 10360
(2012/08/08)
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- On the Reactivity of o-Lithioaryl Ethers: Tandem Anion Translocation and Wittig Rearrangement
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(matrix presented) Allyl and benzyl 2-lithioaryl ethers, generated by bromine-lithium exchange in THF, undergo a new tandem anion translocation-[1,2]-Wittig rearrangement allowing the isolation of the corresponding benzylic alcohols.
- Barluenga, Jose,Fananas, Francisco J.,Sanz, Roberto,Marcos, Cesar,Trabada, Marta
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p. 1587 - 1590
(2007/10/03)
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- Thermodynamic, spectroscopic, and density functional theory studies of allyl aryl and prop-1-enyl aryl ethers. Part 1. Thermodynamic data of isomerization
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A chemical equilibration study of the relative thermodynamic stabilities of seventy isomeric allyl aryl ethers (a) and (Z)-prop-1-enyl aryl ethers (b) in DMSO solution has been carried out. From the variation of the equilibrium constant with temperature the Gibbs energies, enthalpies, and entropies of isomerization at 298.15 K have been evaluated. Because of their low enthalpies, the (Z)-prop-1-enyl aryl ethers are strongly favored at equilibrium, the Gibbs energies of the a→b isomerization ranging from -12 to -23 kJ mol-1. The entropy contribution is negligible in most reactions, but occasionally small positive values less than +10 J K-1 mol-1 of the entropy of isomerization are found. The equilibration studies were also extended to involve two pairs of related isomeric ethers with a Me substituent on C(2) of the olefinic bond. The Me substituent was found to increase the relative thermodynamic stability of the allylic ethers by ca. 3.4 kJ mol-1.
- Taskinen, Esko
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p. 1824 - 1834
(2007/10/03)
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- Isomerisation of Allyl Ethers to Vinyl Ethers catalysed by Palladium on Carbon
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Several allyl ethers are cleanly converted into the corresponding prop-1-enyl ethers on heating in benzene or toluene in the presence of palladium on carbon.
- Carless, Howard A. J.,Haywood, David J.
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p. 980 - 981
(2007/10/02)
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