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16 results on '"Leonov, Artem"'

4. Digitization and validation of a chemical synthesis literature database in the ChemPU

Author

Rohrbach, Simon, primary, Šiaučiulis, Mindaugas, additional, Chisholm, Greig, additional, Pirvan, Petrisor-Alin, additional, Saleeb, Michael, additional, Mehr, S. Hessam M., additional, Trushina, Ekaterina, additional, Leonov, Artem I., additional, Keenan, Graham, additional, Khan, Aamir, additional, Hammer, Alexander, additional, and Cronin, Leroy, additional

Published
2022
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15. Standardization and Control of Grignard Reactions in a Universal Chemical Synthesis Machine using online NMR.

Author

Bornemann-Pfeiffer M, Wolf J, Meyer K, Kern S, Angelone D, Leonov A, Cronin L, and Emmerling F

Abstract

A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. "Chemputer" which is capable of small-molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online-NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements., (© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Published
2021
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16. Fine-tuning the nucleophilic reactivities of boron ate complexes derived from aryl and heteroaryl boronic esters.

Author

Berionni G, Leonov AI, Mayer P, Ofial AR, and Mayr H

Abstract

Boron ate complexes derived from thienyl and furyl boronic esters and aryllithium compounds have been isolated and characterized by X-ray crystallography. Products and mechanisms of their reactions with carbenium and iminium ions have been analyzed. Kinetics of these reactions were monitored by UV/Vis spectroscopy, and the influence of the aryl substituents, the diol ligands (pinacol, ethylene glycol, neopentyl glycol, catechol), and the counterions on the nucleophilic reactivity of the boron ate complexes were examined. A Hammett correlation confirmed the polar nature of their reactions with benzhydrylium ions, and the correlation lg k(20 °C)=sN (E+N) was employed to determine the nucleophilicities of the boron ate complexes and to compare them with those of other borates and boronates. The neopentyl and ethylene glycol derivatives were found to be 10(4) times more reactive than the pinacol and catechol derivatives., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2015
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