- An Efficient Ga(OTf)3/Isopropanol Catalytic System for Direct Reduction of Benzylic Alcohols
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This study aims to report the first gallium-catalyzed direct reduction of benzylic alcohols using isopropanol as a reductant. The reaction proceeds via gallium catalyst-assisted hydride transfer of the in situ-generated benzylic isopropyl ether. The method generates only water and acetone as byproducts and thus provides an atom-economic and environmentally friendly approach to the synthesis of di- and triarylmethanes, which are important substructures in various bioactive compounds and functional materials. (Figure presented.).
- Sai, Masahiro
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supporting information
p. 4330 - 4335
(2018/10/15)
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- Oxidative gold catalysis meets photochemistry - Synthesis of benzo[a]fluorenones from diynes
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Diynes bearing one terminal and one triarylmethylsubstituted alkyne were converted into complex benzofluorenone derivatives via a one-pot process involving a gold-catalyzed step followed by a photocyclization/oxidation. In the first step an Noxide was used to position-selectively generate an a-oxo carbenoid at the terminal alkyne which after a regioselective 1,6-carbene transfer along the tethered tritylalkyne and a subsequent aryl 1,2-shift furnished tetraphenylethylene-like derivatives. These intermediates were successfully transformed to fluorenones via oxidative photocyclization.
- N?sel, Pascal,Moghimi, Setareh,Hendrich, Christoph,Haupt, Marten,Rudolph, Matthias,Rominger, Frank,Hashmia, A. Stephen K.
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supporting information
p. 3755 - 3760
(2015/01/09)
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- Steric, hydrogen-bonding and structural heterogeneity effects on the nucleophilic substitution of N-(p-fluorophenyldiphenylmethyl)-4-picolinium chloride in ionic liquids
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The nucleophilic substitution of N-(p-fluorophenyldiphenylmethyl)-4- picolinium chloride was investigated using water and a range of alcoholic nucleophiles in ionic liquid solvents. The reactivity patterns across the nucleophiles examined could be attributed to steric factors, which mediated the relative nucleophilicities. Reducing the hydrogen-bond acidity of the ionic liquid cation was found to generally increase the rate of reaction, however, the magnitude of this rate effect could be influenced by the steric bulk of the nucleophile and the structural heterogeneity of the ionic liquid. Preferential solvation phenomena in binary mixtures of ionic liquids were examined and suggest that the mechanism behind the hydrogen-bond solvation phenomenon arises from direct cation-mediated, rather than indirect anion-mediated, effects. The Royal Society of Chemistry 2013.
- Weber, Cameron C.,Masters, Anthony F.,Maschmeyer, Thomas
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supporting information
p. 2534 - 2542
(2013/06/05)
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- Rhodium(I)/diene-catalyzed addition reactions of arylborons with ketones
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Rh(I)/diene-catalyzed addition reactions of arylboroxines/arylboronic acids with unactivated ketones to form tertiary alcohols in good to excellent yields are described. By using C2-symmetric (3aR,6aR)-3,6-diaryl-1,3a,4,6a- tetrahydropentalenes as ligands, the asymmetric version of such an addition reaction, with up to 68% ee, was also realized.
- Liao, Yuan-Xi,Xing, Chun-Hui,Hu, Qiao-Sheng
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supporting information; experimental part
p. 1544 - 1547
(2012/06/05)
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- Controlling hydrolysis reaction rates with binary ionic liquid mixtures by tuning hydrogen-bonding interactions
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The ability of a binary ionic liquid (IL) system consisting of a phosphonium transition state analogue (TSA) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][NTf2]) to accelerate the rate of the well-studied hydrolysis of a tert-alkyl picolinium salt by influencing the solvent structure was investigated. A significant rate enhancement was observed in the presence of the TSA; however, comparison with other cations illustrated that this enhancement was not unique to the chosen TSA. Instead, the rate enhancements were correlated with the dilution of hydrogen bonding by the added cations. This phenomenon was further examined by the use of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ([BMMIM][NTf2]) as a cosolvent and the use of Reichardt's dye to measure the extent of hydrogen bonding on solutes in these systems. The rate increases are rationalized in terms of weaker hydrogen bonding from the solvent system to water. ? 2012 American Chemical Society.
- Weber, Cameron C.,Masters, Anthony F.,Maschmeyer, Thomas
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scheme or table
p. 1858 - 1864
(2012/05/20)
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- Pseudo-encapsulation-nanodomains for enhanced reactivity in ionic liquids
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Domain constrained: Polar and nonpolar domains within 1-alkyl-3- methylimidazolium ionic liquids can affect reaction outcomes by pseudo-encapsulation of reactants and this has been explored for a nucleophilic substitution reaction using a cationic substrate and a range of nucleophiles. The significant rate enhancements observed correlate with the concentration of the polar reactants within the ionic liquid's polar domain. ([C nMIM]=1-alkyl-3-methylimidazolium). Copyright
- Weber, Cameron C.,Masters, Anthony F.,Maschmeyer, Thomas
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supporting information
p. 11483 - 11486
(2013/01/15)
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- Novel inhibitors of the gardos channel for the treatment of sickle cell disease
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Sickle cell disease (SCD) is a hereditary condition characterized by deformation of red blood cells (RBCs). This phenomenon is due to the presence of abnormal hemoglobin that polymerizes upon deoxygenation. This effect is exacerbated when dehydrated RBCs experience a loss of both water and potassium salts. One critical pathway for the regulation of potassium efflux from RBCs is the Gardos channel, a calcium-activated potassium channel. This paper describes the synthesis and biological evaluation of a series of potent inhibitors of the Gardos channel. The goal was to identify compounds that were potent and selective inhibitors of the channel but had improved pharmacokinetic properties compared to 1, Clotrimazole. Several triarylamides such as 10 and 21 were potent inhibitors of the Gardos channel (IC50 of 10 nM) and active in a mouse model of SCD. Compound 21 (ICA-17043) was advanced into phase 3 clinical trials for SCD.
- McNaughton-Smith, Grant A.,Burns, J. Ford,Stocker, Jonathan W.,Rigdon, Gregory C.,Creech, Christopher,Arlington, Susan,Shelton, Tara,De Franceschi, Lucia
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p. 976 - 982
(2008/12/20)
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