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Gramüller, Johannes ; Dullinger, Philipp ; Horinek, Dominik ; Gschwind, Ruth M.

Bidentate Substrate Binding in Brønsted Acid Catalysis: Structural Space, Hydrogen Bonding and Dimerization

Gramüller, Johannes, Dullinger, Philipp, Horinek, Dominik und Gschwind, Ruth M. (2022) Bidentate Substrate Binding in Brønsted Acid Catalysis: Structural Space, Hydrogen Bonding and Dimerization. Chemical Science 13 (48), S. 14366-14372.

Veröffentlichungsdatum dieses Volltextes: 19 Dez 2022 09:35
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.53280


Zusammenfassung

BINOL derived chiral phosphoric acids (CPAs) are a prominent class of catalysts in the field of asymmetric organocatalysis, capable of transforming a wide selection of substrates with high stereoselectivities. Exploiting the Brønsted acidic and basic dual functionality of CPAs, substrates with both a hydrogen bond acceptor and donor functionality are frequently used as the resulting bidentate ...

BINOL derived chiral phosphoric acids (CPAs) are a prominent class of catalysts in the field of asymmetric organocatalysis, capable of transforming a wide selection of substrates with high stereoselectivities. Exploiting the Brønsted acidic and basic dual functionality of CPAs, substrates with both a hydrogen bond acceptor and donor functionality are frequently used as the resulting bidentate binding via two hydrogen bonds is expected to strongly confine the possible structural space and thus yield high stereoselectivities. Despite the huge success of CPAs and the popularity of a bidentate binding motif, experimental insights into their organization and origin of stereoinduction are scarce. Therefore, in this work the structural space and hydrogen bonding of CPAs and N-(ortho-hydroxyaryl) imines (19 CPA/imine combinations) was elucidated by low temperature NMR studies and corroborated by computations. The postulated bidentate binding of catalyst and substrate by two hydrogen bonds was experimentally validated by detection of trans-hydrogen bond scalar couplings. Counterintuitively, the resulting CPA/imine complexes showed a broad potential structural space and a strong preference towards the formation of [CPA/imine]2 dimers. Molecular dynamics simulations showed that in these dimers, the imines form each one hydrogen bond to two CPA molecules, effectively bridging them. By finetuning steric repulsion and noncovalent interactions, rigid and well-defined CPA/imine monomers could be obtained. NOESY studies corroborated by theoretical calculations revealed the structure of that complex, in which the imine is located in between the 3,3’-substituents of the catalyst and one site of the substrate is shielded by the catalyst, pinpointing the origin or stereoselectivity for downstream transformations.



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Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftChemical Science
Verlag:Royal Society of Chemistry (RSC)
Band:13
Nummer des Zeitschriftenheftes oder des Kapitels:48
Seitenbereich:S. 14366-14372
Datum25 November 2022
InstitutionenChemie und Pharmazie > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind
Chemie und Pharmazie > Institut für Physikalische und Theoretische Chemie > Lehrstuhl für Chemie IV - Physikalische Chemie (Solution Chemistry) > Prof. Dr. Dominik Horinek
Identifikationsnummer
WertTyp
10.1039/D2SC05076EDOI
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 540 Chemie
StatusVeröffentlicht
BegutachtetJa, diese Version wurde begutachtet
An der Universität Regensburg entstandenJa
URN der UB Regensburgurn:nbn:de:bvb:355-epub-532804
Dokumenten-ID53280

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