- Deracemizing α-Branched Carboxylic Acids by Catalytic Asymmetric Protonation of Bis-Silyl Ketene Acetals with Water or Methanol
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We report a highly enantioselective catalytic protonation of bis-silyl ketene acetals. Our method delivers α-branched carboxylic acids, including nonsteroidal anti-inflammatory arylpropionic acids such as Ibuprofen, in high enantiomeric purity and high yields. The process can be incorporated in an overall deracemization of α-branched carboxylic acids, involving a double deprotonation and silylation followed by the catalytic asymmetric protonation.
- Mandrelli, Francesca,Blond, Aurélie,James, Thomas,Kim, Hyejin,List, Benjamin
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supporting information
p. 11479 - 11482
(2019/07/18)
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- One-pot synthesis of 3-hydroxymaleic anhydrides by cyclization of 1,1-bis(trimethylsilyloxy)ketene acetals with oxalyl chloride
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Functionalized 3-hydroxymaleic anhydrides were prepared by cyclization of 1,1-bis(trimethylsilyloxy)ketene acetals with oxalyl chloride.
- Rotzoll, Sven,Ullah, Ehsan,G?rls, Helmar,Fischer, Christine,Langer, Peter
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p. 2647 - 2656
(2007/10/03)
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- Synthesis of 7,8-benzo-9-aza-4-oxabicyclo[3.3.1]nonan-3-ones by sequential 'condensation-iodolactonization' reactions of 1,1-bis(trimethylsilyloxy)ketene acetals with isoquinolines
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Functionalized 7,8-benzo-9-aza-4-oxabicyclo[3.3.1]nonan-3-ones were prepared by regio- and diastereoselective condensation of 1,1-bis(silyloxy) ketene acetals with isoquinolinium salts and subsequent regioselective and stereospecific iodolactonization.
- Ullah, Ehsan,Rotzoll, Sven,Schmidt, Andreas,Michalik, Dirk,Langer, Peter
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p. 8997 - 8999
(2007/10/03)
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- One-pot synthesis of 3-hydroxymaleic anhydrides by cyclization of 1,1-bis(trimethylsilyloxy)ketene acetals with oxalyl chloride
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Functionalized 3-hydroxymaleic anhydrides were prepared by cyclization of 1,1-bis(trimethylsilyloxy)ketene acetals with oxalyl chloride.
- Ullah, Ehsan,Langer, Peter
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p. 2782 - 2784
(2007/10/03)
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- An efficient α-hydroxylation of carbonyls using the HOF·CH3CN complex
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The complex HOF·CH3CN, made directly from fluorine and aqueous acetonitrile, was used for α-hydroxylation of various ketones, esters and acids via their trimethyl silyl enol ethers. The reaction is usually complete in a few minutes at room temperature or below and has high yields.
- Dayan, Sharon,Bareket, Yifat,Rozen, Shlomo
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p. 3657 - 3664
(2007/10/03)
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- STRUCTURE DU REACTIF D'IVANOV ET DE QUELQUES ORGANOMETALLIQUES ISSUS DES DERIVES PHENYLACETIQUES-I. ETUDE DES SOLUTIONS PAR RMN
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Ivanov reagent and several analogous reagents (phenyl acetique serie) have been studied by NMR.In all the cases, an enolate-structure is revealed; no carbaneniate-species could be detected, even in very solvating solvents.
- Mladenova, M.,Blagoev, B.,Gaudemar, M.,Dardoize, F.,Lallemand, J. Y.
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p. 2153 - 2156
(2007/10/02)
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- Synthesis of α-fluorocarbonyl compounds
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Process for preparing an organic compound of the formula R2 R2 CFC(O)R3, which process comprises contacting and reacting in a reaction mixture which includes an inert solvent, at a temperature of -40° C. to -100° C., ROF and STR1 R is polyfluoroperhaloalkyl of 1-6 carbon atoms or FOCF2 ; R1 is hydrocarbyl of 1-6 carbon atoms; each R2 is selected from H, alkyl of 1-17 carbon atoms, cycloalkyl of 3-6 carbon atoms, aryl, heteroaryl and such alkyl, cycloalkyl, aryl and heteroaryl substituted by halogen or alkoxy of 1-6 carbon atoms; R3 is selected from H, alkyl and haloalkyl of 1-16 carbon atoms, cycloalkyl of 3-10 carbon atoms, aryl and haloaryl, OSi(R1)3, OH, NH2, alkoxy of 1-6 carbon atoms, aryloxy, NHR1 and NR12 wherein R1 is alkyl of 1-6 carbon atoms, N-arylamino and nitrogen or sulfur heterocyclic of 4-5 carbon atoms; R3 and one R2 taken together is a diradical which with the C=C group is carbocyclic, heterocyclic or haloheterocyclic, and recovering from the reaction mixture the compound of the formula R2 R2 CFC(O)R3.
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