17463-01-3Relevant academic research and scientific papers
A practical, efficient, and atom economic alternative to the Wittig and Horner-Wadsworth-Emmons reactions for the synthesis of (E)-α,β- unsaturated esters from aldehydes
List, Benjamin,Doehring, Arno,Hechavarria Fonseca, Maria T.,Job, Andreas,Rios Torres, Ramon
, p. 476 - 482 (2007/10/03)
We describe a highly efficient new methodology for the synthesis of (E)-α,β-unsaturated esters from aldehydes. In our DMAP-catalyzed reaction, both aromatic as well as aliphatic aldehydes furnish the desired products highly regio- and stereoselectively if treated with commercially available or synthetically easily accessible malonic acid half ester. A large scale application in the synthesis of p-methoxycinnamates, which are of use as sunscreen ingredients, is described.
TMSCl-mediated catalytic carbocupration of alkynoates: An unprecedented and remarkable effect of catalyst loading on highly selective stereochemical induction via a TMS-allenoate intermediate
Jennings, Michael P.,Sawant, Kailas B.
, p. 3201 - 3204 (2007/10/03)
The TMSCl-mediated catalytic carbocupration of alkynoates has been investigated. It has been shown that catalyst loadings as low as 30 mol% readily allow for high yields and diastereoselectivities for a series of Grignard reagents. In addition, an unprecedented and remarkable effect of catalyst loading on stereochemical induction has been observed. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
New solid-supported phosphonate reagents for the synthesis of Z-α,β-unsaturated esters
Martina, Sébastien L. X.,Taylor, Richard J. K.
, p. 3279 - 3282 (2007/10/03)
Novel solid-supported phosphonate reagents have been prepared and evaluated for the synthesis of α,β-unsaturated esters with a preference for the Z-alkene. The optimal reagent was a hybrid of both Still-Gennari and Ando reagents, and showed good to high yields and fair to good Z-selectivity for the conversion of both aliphatic and aromatic aldehydes.
REACTIONS DE WITTIG-HORNER ET DE TRANSESTERIFICATION EN UNE OPERATION PAR ACTIVATION ANIONIQUE DE LIAISONS C-H ET O-H EN MILIEU HETEROGENE CARBONATE DE POTASSIUM/ALCOOL
Mouloungui, Z.,Elmestour, R.,Delmas, M.,Gaset, A.
, p. 1219 - 1232 (2007/10/02)
The Wittig-Horner reaction carried out in various alcohols is accompanied by transesterification of the alkyl radical of the α,β-ethylenic ester formed.The occurrence of these two reactions in the same reaction medium is affected by the behavior of: i) the alcohol (solvent and reagent), ii) potassium carbonate (reagent and catalyst).The propensity for the two reactions to occur was found to depend on the polarity of the alcohol.Protic alcohols speeded both the Wittig-Horner and the subsequent transesterification reaction.Both reactions were quantitative despite the use of non-stoichiometric amounts of potassium carbonate.Regeneration in situ of the solid base observed in aprotic medium was markedly enhanced under these reaction conditions.The mechanism proposed for these two reactions incorporates this regeneration process.
The Horner-Wadsworth-Emmons Modification of the Wittig Reaction Using Triethylamine and Lithium or Magnesium Salts
Rathke, Michael W.,Nowak, Michael
, p. 2624 - 2626 (2007/10/02)
A variety of aldehydes were converted into the corresponding α,β-unsaturated esters using triethyl phosphonoacetate and triethylamine in the presence of lithium or magnesium halides.Under the same conditions, simple methyl ketones were unreactive.
