- Synthesis of 3-substituted 2-cyclohexenones through umpoled functionalization
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A new protocol to obtain 3-substituted 2-cyclohexenones, was developed by reversing the chemical reactivity of 2-cyclohexenone. One-pot synthesis of 3-substituted 2-cyclohexenones can be achieved by treatment of 3-phenylthiosilyl enol ether with a mixture of t-BuLi/HMPA that allows hydrogen-selective exchange in presence of reactive electrophiles such as aldehydes, ketones and alkyl halides. This affords the corresponding product in moderate overall yield, after silyl enol ether cleavage and concomitant thiophenol elimination initiated with TBAF.
- Lechuga-Eduardo, Harim,Zarza-Acu?a, Eduardo,Romero-Ortega, Moisés
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p. 3234 - 3237
(2017/07/27)
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- KMnO4-mediated oxidation as a continuous flow process
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An efficient and easily scalable transformation of alcohols and aldehydes to carboxylic acids and nitroalkane derivatives to the corresponding carbonyls and carboxylic acids using permanganate as the oxidant within a continuous flow reactor is reported. Notably, the generation and downstream processing of MnO2 slurries was not found to cause any blocking of the reactor when ultrasound pulses were applied to the flow system.
- Sedelmeier, Joerg,Ley, Steven V.,Baxendale, Ian R.,Baumann, Marcus
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supporting information; experimental part
p. 3618 - 3621
(2010/11/17)
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- Cyclization reactions through DDQ-mediated vinyl oxazolidinone oxidation
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Vinyl oxazolidinones react with DDQ to form α,β-unsaturated acyliminium ions in a new method for forming electrophiles under oxidative conditions. Appended nucleophiles undergo 1,4-addition reactions with these intermediates to form cyclic vinyl oxazolidinones with good levels of diastereocontrol, highlighting a new approach to utilizing oxidative carbon-hydrogen bond functionalization to increase molecular complexity.
- Liu, Lei,Floreancig, Paul E.
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supporting information; experimental part
p. 3152 - 3155
(2009/12/05)
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- Novel β-masked formylation of α,β-unsaturated ketones and lactones by tetra-n-butylammonium sulfate radical
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Tetra-n-butylammonium peroxydisulfate was prepared and found to be a good source of tetra-n-butylammonium sulfate radical by its oxygen -oxygen bond cleavage. The sulfate radical can be utilized for the efficient organic syntheses in organic solvents. Ele
- Kim, Yong Hae,Choi, Hyun Chul
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p. 327 - 328
(2007/10/03)
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- 4-Isopropyl-2-oxazolin-5-one anion as masked umpoled synthon for both formyl and hydroxycarbonyl anions: Generation, reactivity and synthetic applications
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The anion of the title compound, simply generated in the presence of catalytic amount of triethylamine, reacts with both common electrophilic olefins and aldehydes to give moderate to good yield of Michael or aldol adducts respectively. Mild acid treatment of these adducts at ambient temperature serves to demask the aldehyde function, allowing one to consider the anion of 1 as a nucleophilic acylating equivalent of formaldehyde. On the other hand, the same anion of 1 may act as a masked umpoled synthon for a hydroxycarbonyl anion since its aldol adducts with aldehydes undersent concomitant isomerization and ring cleavage under mild basic conditions producing dipeptides which could be hydrolyzed to give the corresponding carboxylic acids. Synthetic applications of this chemistry in the area of sugar, aminosugar and non-proteinogenic aminoacid derivatives are discussed.
- Barco, Achille,Benetti, Simonetta,De Risi, Carmela,Pollini, Gian P.,Spalluto, Giampiero,Zanirato, Vinicio
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p. 4719 - 4734
(2007/10/03)
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- 4-Isopropyl-2-oxazolin-5-one anion as a new convenient formyl anion equivalent for conjugate addition and aldol reactions
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The anion of the title compound, simply generated in the presence of catalytic amount of triethylamine, acts as nucleophilic acylating equivalent of formaldehyde reacting with both common electrophilic olefins or aldehydes to give moderate to good yield of Michael or aldol adducts respectively, which are easily hydrolized by dilute acid at ambient to temperature to afford the corresponding aldehydes.
- Barco, Achille,Benetti, Simonetta,De Risi, Carmela,Pollini, Gian P.,Spalluto, Giampiero,Zanirato, Vinicio
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p. 3907 - 3910
(2007/10/02)
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- Pharmaceutically active amines
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The aromatic amines (I), alkyl amines (II), bicyclic amines (III). STR1 cycloalkyl amines (IV), aromatic bicyclic amines (V), hydroquinone amines (VI), quinone amines (VII), amino-ethers (VIII) and bicyclic amino ethers (IX) are useful as pharmaceutical agents for treating a number of conditions including spinal trauma, mild and/or moderate to severe head injury, etc. Also disclosed is a method of treatment using the 3,4-dihydrobenzopyrans (XI).
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- CONJUGATE ADDITION OF N-SUBSTITUTED ORGANO(SILYLIMINOMETHYL)COPPER(I) TO α,β-UNSATURATED CARBONYL COMPOUNDS
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The organocopper reagent prepared from lithium undergoes the conjugate addition to α,β-unsaturated carbonyl compounds to produce γ-(2,6-xylylimino)-γ-(trialkylsilyl)carbonyl compounds or the organosilyl ethers of th
- Murakami, Masahiro,Matsuura, Takaharu,Ito, Yoshihiko
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p. 355 - 358
(2007/10/02)
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- REGIOSELECTIVE SYNTHETIC ROUTES TO 1,4-DICARBONYL COMPOUNDS AND SOME α-HYDROXY CARBONYL COMPOUNDS FROM 1,1-BIS(THIO)- AND BIS(SELENO)-ALLKYLLITHIUMS
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CuCl2/CuO was found to be a particularly valuable combination for the transformation of functionalized thio- and seleno-ketals to the corresponding aldehydes and ketones.
- Lucchetti, Jean,Krief, Alain
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p. 1153 - 1162
(2007/10/02)
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