54860-39-8Relevant academic research and scientific papers
Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles
Drikermann, Denis,G?rls, Helmar,Kerndl, Valerie,Vilotijevic, Ivan
, p. 1158 - 1162 (2020/07/20)
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95percent. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- A nd tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.
Highly regioselective palladium-catalysed oxidative allylic C-H carbonylation of alkenes
Chen, Huoji,Cai, Congbi,Liu, Xiaohang,Li, Xianwei,Jiang, Huanfeng
supporting information; experimental part, p. 12224 - 12226 (2011/12/14)
Pd-catalysed direct oxidative carbonylation of allylic C-H bonds with carbon monoxide was first described. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalysed allylic carbonylation can be lifted, which provides a new route for accessing more synthetically useful β-enoic acid esters with high regioselectivity. The Royal Society of Chemistry 2011.
Asymmetric dihydroxylation of β,γ-unsaturated carboxylic esters with trisubstituted C=C bonds - Enantioselective syntheses of trisubstituted γ-butyrolactones
Kapferer, Tobias,Brueckner, Reinhard
, p. 2119 - 2133 (2007/10/03)
β,γ-Unsaturated esters with stereodefined trisubstitued C=C double bonds were prepared by the Arndt-Eistert homologation of α,β-unsaturated carboxyl halides, by two-step methoxycarbonylation of allylbarium reagents, by deconjugation of α,β-unsaturated esters, and by Horner-Wadsworth-Emmons variants of the Stobbe condensation. Sharpless asymmetric dihydroxylation of the β,γ-unsaturated esters, followed by spontaneous cyclization, afforded β-hydroxy-γ-lactones in moderate to good yields and with enantiomeric excesses of up to 97 %. Similarly, tetrahydroxy-γ-lactones were obtained from diunsaturated esters; these lactones were converted into a bislactone and an unsaturated β-hydroxy γ-lactone. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Enecarboxylation with Diethyl Oxomalonate as an Enophilic Equivalent of Carbon Dioxide. A Synthesis of Allylcarboxylic Acids
Salomon, Mary F.,Pardo, Simon N.,Salomon, Robert G.
, p. 3797 - 3802 (2007/10/02)
Allylcarboxylic acids are prepared from alkenes by a two-stage process which is synthetically equivalent to an ene reaction of carbon dioxide: (1) ene reaction with diethyl oxomalonate to afford an α-hydroxylmalonic ester and (2) oxidative bisdecarboxylation of the derived α-hydroxymalonic acid.The oxidative bisdecarboxylation of α-hydroxymalonic acids can sometimes be achieved with sodium periodate.However, occasionally decarboxylation is only partial, leading to pyruvic rather than carboxylic acids.While the bisdecarboxylations with periodate have previously been "buffered with a little pyridine", the latter is now shown to inhibit the reaction.In fact the pyruvate:carboxylate ratio can be a sensitive function of the amount of pyridine present in the reaction mixture, and the oxidative decarboxylation can be controlled to yield almost exclusively carboxylic or pyruvic acid.An effective new reagent, ceric ammonium nitrate in aqueous acetonitrile, was discovered for oxidative bisdecarboxylation of α-hydroxymalonic acids.Fortunately this reagent provides good to excellent yields of allylcarboxylic acids in many cases for which sodium periodate proved unsatisfactory.
Reactivity of 1-Cyclopropene-1-carboxylic Acid Lactones Dependent on the Size of the Lactone Ring
Frenking, Gernot,Huelskaemper, Ludwig,Weyerstahl, Peter
, p. 2826 - 2835 (2007/10/02)
The reaction of the bicyclic γ-lactone 1 with KOtBu leads to lactone 3 by addition of tert-butoxide at the 1-position of the intermediate cyclopropene lactone 2 and subsequent exo-protonation.In contrast, the δ-lactone 13, readily available from cinnamyl
