evidence for the structures of a number of rearrangement products has been given [120,121] and the reaction mechanism was established in 1976 by Wawzonek and Durham [122].Ethylacetoacetategives butane by reduction under acid conditions [119], probably by the Tafel rearrangement mechanism. ...
(S)-Tol-MeO-BIPHEP, and DFT calculations for the reaction pathway of the AAA reaction mediated by an isolated olefin-coordinated nickel-DPPF complex 4b, we propose a mechanism where protonation of the nitrogen atom of the coordinating allylic amine by beta-ketoester is key to cleaving the C-...
Moreover, β-aminoester 5d was obtained with excellent control of all three contiguous stereogenic centers. From mechanism studies it was suggested that the chelation of the imino group and the ester enolate by the manganese ion facilitates cyclization which leads to exclusive cis diastereoselectivity....
The mechanism of DNA polymerase beta-catalyzed nucleotidyl transfer consists of chemical steps involving primer 3' OH deprotonation, nucleophilic attack, a... CA Sucato,TG Upton,BA Kashemirov,... - 《Biochemistry》 被引量: 86发表: 2008年 ...
44) [67]. The mechanism of the reaction involves an initial base-catalyzed condensation of 2-cyanobenzaldehydes and 2-isocyanoacetates, followed by a cascade intramolecular cyclization-ring opening rearrangement-6-exo cyclization-decarbonylation-aromatization sequence. Sign in to download full-size ...
Proposed mechanism in the Borrmann and Wegler example involves an aldol-lactonization process. The Wynberg β-lactone synthesis was one of the first practical, catalytic, asymmetric reactions,231,232 in which quinidine and quinine were found to be good catalysts for the formal [2+2] ...
However, the reaction mechanism is still unclear becausenone of the intermediates was observed during the reaction process.In this work, we employed theoretical and computational chemistryto investigate the possible pathway. Finally, the calculated resultsindicate that ketene formed by the Wolff ...
N-substituted 1,4-dihydropyridines bearing a carboxyl group at the 4-position were synthesized in solvent-free conditions with Cu(2+) as the catalyst, imine and ketoester as starting materials. The possible mechanism which consists of addition-rearrangement process was proposed and examined by the...
CURT WENTRUP, GERHARD GROSS, HANS MICHAEL BERSTERMANN, PRIMOZ LORENCAK: "Mechanism of fragmentation of alkylidene-Meldrum's acids. Carboxyketene, vinylketene, and methyleneketene intermediates from 5-cyclopentylidene-2,2-dimethyl-1,3-dioxan e-4,6-dione", JOURNAL OF ORGANIC CHEMISTRY, vol. 50, ...
Similar mechanism has been elucidated in uterine leiomyoma (uterine fibroids) and endometrial hyperplasia. Reduction of the endogenous estradiol concentration in affected tissues will result in reduced or impaired proliferation of 17β-estradiol cells in said tissues and may thus be utilized in prevention...