98066-39-8Relevant articles and documents
Allenic Esters from Cyclopropenones by Lewis Base Catalysis: Substrate Scope, the Asymmetric Variant from the Dynamic Kinetic Asymmetric Transformation, and Mechanistic Studies
Wei, Yin,Zhao, Wen-Tao,Yang, Yuan-Liang,Zhang, Zhen,Shi, Min
, p. 3340 - 3349 (2015)
The Lewis base catalyzed reactions of cyclopropenones with a variety of nucleophiles (alcohols, phenols, or water) were systematically investigated. We demonstrated that this kind of reaction could be used to synthesize allenic esters in moderate to excellent yields. Furthermore, more synthetically interesting axially chiral allenes in moderate to good yields and ee values were obtained in the corresponding asymmetric reaction in the presence of multifunctional chiral phosphine catalyst. The reaction mechanism was disclosed by using NMR tracing experiments, MS, and DFT calculations. Notably, the asymmetric reaction was proved to be a dynamic kinetic asymmetric transformation based on the control experiments, and the detailed mechanism of this transformation revealed by theoretical investigations.
Chemistry of Cumulenes, 6. Syntheses and Reactions of 1-H-Allene-1,3-dicarboxylic Acid Monoesters
Nader, Franz W.,Brecht, Angelika,Kreisz, Siegfried
, p. 1196 - 1207 (2007/10/02)
The title compounds 5a-e have been prepared.The carboxylation of allene monoesters 4 was successful with the phenyl derivative 4a only.The resulting extremely unstable halfester 5a as its benzylammonium salt was spontaneously transformed into the enamine ester 7.The alkyl-substituted allenes 5b-e are accessible via Wittig reaction of alkylmalonic monoester chlorides 11 with (alkoxycarbonyl)methylene ylides 12, which comprise the 2,2,2-trichloroethyl or the tert-butyl residues as selectively cleavable carboxylic protecting groups.Cleavage of the CCl3CH2 group with Zn succeeded for the tert-butylallenes 13a/b only.In the case of the methylallene 13c the cleavage was accompanied by hydrogenation of the allene.The mechanism of this reaction is discussed.Cleavage of the tert-butyl ester group in 13d and e was readily achieved with ether/sulfuric acid.