- Selective Acylation of Aryl- A nd Heteroarylmagnesium Reagents with Esters in Continuous Flow
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A selective acylation of readily accessible organomagnesium reagents with commercially available esters proceeds at convenient temperatures and short residence times in continuous flow. Flow conditions allow us to prevent premature collapse of the hemiacetal intermediates despite noncryogenic conditions, thus furnishing ketones in good yields. Throughout, the coordinating ability of the ester and/or Grignard was crucial for the reaction outcome. This was leveraged by the obtention of several bisaryl ketones using 2-hydroxy ester derivatives as substrates.
- Heinz, Benjamin,Djukanovic, Dimitrije,Ganiek, Maximilian A.,Martin, Benjamin,Schenkel, Berthold,Knochel, Paul
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supporting information
p. 493 - 496
(2020/01/31)
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- Palladium on Carbon-Catalyzed Chemoselective Oxygen Oxidation of Aromatic Acetals
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The development of an unprecedented chemoselective transformation has contributed to forming a novel synthetic process for target molecules. Chemoselective oxidation of aromatic acetals has been accomplished using a reusable palladium on carbon catalyst under atmospheric oxygen conditions to form ester derivatives with tolerance of aliphatic acetals and ketals.
- Yasukawa, Naoki,Asai, Shota,Kato, Maho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
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supporting information
p. 5604 - 5607
(2016/11/17)
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- Towards a sustainable synthesis of aniline-derived amides using an indirect chemoenzymatic process: Challenges and successes
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A general, catalytic and sustainable synthesis of amides has been targeted which utilises a chemoenzymatic step to generate an activated amide coupling partner in situ. A screen of a series of known activating agents was performed and the successful agents taken forward to determine their utility in such a one-pot enzyme-catalysed process. In these studies, a new chemoselective reagent ((isopropylideneamino) 2-phenylacetate) has been identified, which demonstrates excellent selectivity for the acylation of primary anilines over secondary anilines, unlike the more conventional acid chloride equivalent, which is unselective. The development of a chemoenzymatic synthesis of 2-hydroxyethyl benzoates (ethylene glycol mono-benzoate esters) has also been achieved.
- Lal, Samridhi,Snape, Timothy J.
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p. 1609 - 1615
(2014/01/06)
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- Transition metal-free oxidative esterification of benzylic alcohols in aqueous medium
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Oxidative esterification of benzylic alcohols with a catalytic amount of HBr-H2O2 in aqueous medium under mild conditions is reported with a wide range of substrate scope for both benzylic and aliphatic alcohols. The conditions are also suitable for selective mono-esterification of ethylene glycol and glycerol. With catalytic amounts of HBr (20 mol%) and H2O2, the generation of reactive intermediate species BrOH has been ascertained by UV-visible spectra.
- Samanta, Supravat,Pappula, Venkatanarayana,Dinda, Milan,Adimurthy, Subbarayappa
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supporting information
p. 9453 - 9456
(2014/12/11)
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- Rate-acceleration in gold-nanocluster-catalyzed aerobic oxidative esterification using 1,2- and 1,3-diols and their derivatives
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Aerobic oxidation of aldehydes to 1,2- and 1,3-diol monoesters was catalyzed by polymer-incarcerated gold nanoclusters under ambient conditions. The esterification proceeded much faster with 1,2- and 1,3-diols and their derivatives rather than with methanol. Magnum PI: Gold-nanocluster catalysts, PI-Au, that were immobilized on polystyrene-based polymers with cross-linking moieties, were used to catalyze the syntheses of 1,2 and 1,3-diol monoesters and their derivatives from aldehydes. The effect of neighboring-group participation in the esterification reaction is also described. Copyright
- Yasukawa, Tomohiro,Miyamura, Hiroyuki,Kobayashi, Shu
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experimental part
p. 621 - 627
(2011/10/12)
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- Facile oxidative hydrolysis of acetals to esters using hypervalent iodine(III)/LiBr combination in water
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The combination of (diacetoxy)iodobenzene (PhI(OAc)2, DIB) and lithium bromide (LiBr) efficiently oxidized cyclic and acyclic acetals to the corresponding hydroxyalkyl carboxylic esters and simple esters in good to excellent yields. The merits of this reaction are that it employs commercially available and non-explosive hypervalent iodine(III) reagent, water as the solvent, a short reaction time, and mild reaction conditions.
- Panchan, Waraporn,Chiampanichayakul, Supanimit,Snyder, Deanna L.,Yodbuntung, Siriporn,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn,Kuhakarn, Chutima
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experimental part
p. 2732 - 2735
(2010/05/17)
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- 2-Iodoxybenzoic acid/tetraethylammonium bromide/water: An efficient combination for oxidative cleavage of acetals
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A simple and efficient procedure has been developed for the oxidation of cyclic and acyclic acetals to the corresponding hydroxyalkyl carboxylic esters and simple esters, respectively. 2-Iodoxybenzoic acid (IBX) in the presence of tetraethylammonium bromide was employed for the reaction in aqueous media. The salient features of the protocol include short reaction time, environmentally benign reagents and solvent, and moderate to high yields. Georg Thieme Verlag Stuttgart.
- Kuhakarn, Chutima,Panchan, Waraporn,Chiampanichayakul, Supanimit,Samakkanad, Natthapol,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn
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experimental part
p. 929 - 934
(2009/10/14)
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- Oxidation of acetals by dimethyldioxirane
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Kinetic data (k2's, LFER and activation parameters) for the oxidation of a series of acetals by dimethyldioxirane to the corresponding esters in dried acetone are reported; the results are consistent with either a H-atom abstraction or direct insertion mechanism.
- Baumstark,Kovac, Franci,Vasquez, Pedro C.
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