0470637 - ÚOCHB 2017 RIV DE eng J - Článek v odborném periodiku
Procházková, Eliška - Kolmer, A. - Ilgen, J. - Schwab, M. - Kaltschnee, L. - Fredersdorf, M. - Schmidts, V. - Wende, R. C. - Schreiner, P. R. - Thiele, C. M.
Uncovering Key Structural Features of an Enantioselective Peptide-Catalyzed Acylation Utilizing Advanced NMR Techniques.
Angewandte Chemie - International Edition. Roč. 55, č. 51 (2016), s. 15754-15759. ISSN 1433-7851. E-ISSN 1521-3773
Institucionální podpora: RVO:61388963
Klíčová slova: conformational analysis * enantioselective acylations * NMR spectroscopy * pure shift NMR * RDCs
Kód oboru RIV: CC - Organická chemie
Impakt faktor: 11.994, rok: 2016 ; AIS: 3.437, rok: 2016
DOI: https://doi.org/10.1002/anie.201608559

We report on a detailed NMR spectroscopic study of the catalyst-substrate interaction of a highly enantioselective oligopeptide catalyst that is used for the kinetic resolution of trans-cycloalkane-1,2-diols via monoacylation. The extraordinary selectivity has been rationalized by molecular dynamics as well as density functional theory (DFT) computations. Herein we describe the conformational analysis of the organocatalyst studied by a combination of nuclear Overhauser effect (NOE) and residual dipolar coupling (RDC)-based methods that resulted in an ensemble of four final conformers. To corroborate the proposed mechanism, we also investigated the catalyst in mixtures with both trans-cyclohexane-1,2-diol enantiomers separately, using advanced NMR methods such as T-1 relaxation time and diffusion-ordered spectroscopy (DOSY) measurements to probe molecular aggregation. We determined intramolecular distance changes within the catalyst after diol addition from quantitative NOE data. Finally, we developed a pure shift EASY ROESY experiment using PSYCHE homodecoupling to directly observe intermolecular NOE contacts between the trans-1,2-diol and the cyclohexyl moiety of the catalyst hidden by spectral overlap in conventional spectra. All experimental NMR data support the results proposed by earlier computations including the proposed key role of dispersion interaction.
Trvalý link: http://hdl.handle.net/11104/0268217