- Synthesis of Functionalized Aliphatic Acid Esters via the Generation of Alkyl Radicals from Silylperoxyacetals
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We describe a catalytic method for the synthesis of a variety of functionalized aliphatic acid esters using silylperoxyacetals, which are versatile alkyl radical precursors with a terminal ester moiety. In the presence of an appropriate transition-metal catalyst, the in situ generation of alkyl radicals and the subsequent bond-forming process proceeds smoothly to afford synthetically valuable aliphatic acid derivatives. The present method can be applied to the efficient synthesis of a pharmaceutically important 1,1-diarylalkane motif. In addition, a novel strategy for the synthesis of structurally diverse hydroxy acid derivatives via a C?O bond formation process that utilizes TEMPO has been developed.
- Matsumoto, Akira,Shiozaki, Yoko,Sakurai, Shunya,Maruoka, Keiji
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supporting information
p. 2431 - 2434
(2021/08/07)
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- Method for the selective formation of dimethyl acetals in the presence of hydroxylamine
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An inexpensive and mild method for the formation of dimethyl acetals from the corresponding aldehydes is achieved using hydroxylamine and methanol under neutral conditions at room temperature. Notably, the reaction is selective for aldehydes in the presence of ketones, rendering this an example of a chemoselective acetalization. For saturated, sterically accessible aldehydes, catalytic amounts of hydroxylamine may be employed to attain the corresponding dimethyl acetal as the sole product in good to excellent yield. Unsaturated and hindered aldehydes required stoichiometric amounts of hydroxylamine but provided dimethyl acetals as the major product in typically excellent yield. In some cases, the corresponding oxime was also observed but may be separated from the acetal by flash column chromatography or distillation. The involvement of an intermediate oxime compound is postulated. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file. Taylor & Francis Group, LLC.
- Mickelsen, Ky J.,Tajc, Chelsea M.,Greenwood, Kevin R.,Browder, Cindy C.
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experimental part
p. 186 - 194
(2011/10/31)
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- An efficient and versatile procedure for the synthesis of acetals from aldehydes and ketones catalyzed by lithium tetrafluoroborate
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Acetals are obtained in good to excellent yields by treatment of aldehydes and ketones with trialkyl orthoformate and the corresponding alcohol in the presence of a catalytic amount of lithium tetrafluoroborate. Due to the mild reaction conditions, this method is compatible with acid-sensitive substrates.
- Hamada, Nao,Kazahaya, Kiyoshi,Shimizu, Hisashi,Sato, Tsuneo
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p. 1074 - 1076
(2015/10/07)
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- Efficient acetalisation of aldehydes catalyzed by titanium tetrachloride in a basic medium
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The acetalisation of aliphatic and aromatic aldehydes is achieved in a basic medium by using catalytic amount of Ti(IV) chloride in MeOH in the presence of NH3 or Et3N. The present protocol shows many advantages over the well known base or acid catalysis: in fact, in contrast to base-promoted acetalisation, aldehydes with electron-rich carbonyl groups react easily, enolizable aldehydes do not undergo aldol condensation and, in contrast to acid-catalysis, migration of the double bond does not occur in the preparation of α,β-unsaturated acetals.
- Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
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p. 15679 - 15690
(2007/10/03)
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- 70. Cationic Palladium(II), Platinum(II), and Rhodium(I) Complexes as Acetalisation Catalysts
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The use of (CF3SO3)2 as a catalyst for the acetalisation of a variety of aldehydes and ketones and for trans-acetalisation is described.It is also shown that (CF3SO3)2 is at least as effective as the corresponding Pd compound, while much lower reaction rates are observed with
- Gorla, Fabrizio,Venanzi, Luigi M.
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p. 690 - 697
(2007/10/02)
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- Efficient Electrocatalytical Acetalization of Aliphatic Aldehydes
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Aliphatic aldehydes are conveniently acetalized by methanol or 1,2-ethanediol at a platinum or carbon anode.The process is electrocatalytic in character.
- Gora, J.,Smigielski, K.,Kula, J.
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p. 586 - 588
(2007/10/02)
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