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dc.contributor.authorMcLaughlin, Calum
dc.contributor.authorBitai, Jacqueline
dc.contributor.authorBarber, Lydia
dc.contributor.authorSlawin, Alexandra
dc.contributor.authorSmith, Andrew David
dc.identifier.citationMcLaughlin , C , Bitai , J , Barber , L , Slawin , A & Smith , A D 2021 , ' Catalytic enantioselective synthesis of 1,4-dihydropyridines via the addition of C(1)-ammonium enolates to pyridinium salts ' , Chemical Science , vol. Advance Article .
dc.identifier.otherPURE: 275345276
dc.identifier.otherPURE UUID: 7143aab0-1a34-4dea-bd0a-c656fb101d2e
dc.identifier.otherORCID: /0000-0002-2104-7313/work/98487552
dc.identifier.otherORCID: /0000-0002-9527-6418/work/98487670
dc.identifier.otherWOS: 000686800600001
dc.identifier.otherScopus: 85115730140
dc.descriptionAuthors thank the EPSRC (EP/M508214/1, C.M.) for funding. A.D.S. thanks the Royal Society for a Wolfson Research Merit Award.en
dc.description.abstractThe regio- and stereoselective addition of C(1)-ammonium enolates – generated in situ from aryl esters and the isothiourea catalyst (R)-BTM – to pyridinium salts bearing an electron withdrawing substituent in the 3-position allows the synthesis of a range of enantioenriched 1,4-dihydropyridines. This represents the first organocatalytic approach to pyridine dearomatisation using pronucleophiles at the carboxylic acid oxidation level. Optimisation studies revealed a significant solvent dependency upon product enantioselectivity, with only toluene providing significant asymmetric induction. Using DABCO as a base also proved beneficial for product enantioselectivity, while investigations into the nature of the counterion showed that co-ordinating bromide or chloride substrates led to higher product er than the corresponding tetrafluoroborate or hexafluorophosphate. The scope and limitations of this process are developed, with enantioselective addition to 3-cyano- or 3-sulfonylpyridinium salts giving the corresponding 1,4-dihydropyridines (15 examples, up to 95:5 dr and 98:2 er).
dc.relation.ispartofChemical Scienceen
dc.rightsCopyright © 2021 The Author(s). Open Access. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.en
dc.subjectQD Chemistryen
dc.titleCatalytic enantioselective synthesis of 1,4-dihydropyridines via the addition of C(1)-ammonium enolates to pyridinium saltsen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews.School of Chemistryen
dc.contributor.institutionUniversity of St Andrews.EaSTCHEMen
dc.description.statusPeer revieweden

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