000156666 001__ 156666
000156666 005__ 20251017144604.0
000156666 0247_ $$2doi$$a10.1021/jacs.0c05525
000156666 0248_ $$2sideral$$a119147
000156666 037__ $$aART-2020-119147
000156666 041__ $$aeng
000156666 100__ $$aSantana, A.G.
000156666 245__ $$aDissecting the Essential Role of Anomeric ß-Triflates in Glycosylation Reactions
000156666 260__ $$c2020
000156666 5060_ $$aAccess copy available to the general public$$fUnrestricted
000156666 5203_ $$aGlycosylations promoted by triflate-generating reagents are widespread synthetic methods for the construction of glycosidic scaffolds and glycoconjugates of biological and chemical interest. These processes are thought to proceed with the participation of a plethora of activated high energy intermediates such as the a- and ß-glycosyl triflates, or even increasingly unstable glycosyl oxocarbenium-like species, among which only a-glycosyl triflates have been well characterized under representative reaction conditions. Interestingly, the remaining less accessible intermediates, yet to be experimentally described, seem to be particularly relevant in a-selective processes, involving weak acceptors. Herein, we report a detailed analysis of several paradigmatic and illustrative examples of such reactions, employing a combination of chemical, NMR, kinetic and theoretical approaches, culminating in the unprecedented detection and quantification of the true ß-glycosyl triflate intermediates within activated donor mixtures. This achievement was further employed as a stepping-stone for the characterization of the triflate anomerization dynamics, which along with the acceptor substitutions, govern the stereochemical outcome of the reaction. The obtained data conclusively show that, even for highly dissociative reactions involving ß-close ion pair (ß-CIP) species, the formation of the a-glycoside is necessarily preceded by a bimolecular a ¿ ß triflate interconversion, which under certain circumstances becomes the rate-limiting step. Overall, our results rule out the prevalence of the Curtin-Hammett fast-exchange assumption for most glycosylations and highlight the distinct reactivity properties of a- and ß-glycosyl triflates against neutral and anionic acceptors.
000156666 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es
000156666 590__ $$a15.419$$b2020
000156666 591__ $$aCHEMISTRY, MULTIDISCIPLINARY$$b15 / 178 = 0.084$$c2020$$dQ1$$eT1
000156666 592__ $$a7.115$$b2020
000156666 593__ $$aBiochemistry$$c2020$$dQ1
000156666 593__ $$aColloid and Surface Chemistry$$c2020$$dQ1
000156666 593__ $$aChemistry (miscellaneous)$$c2020$$dQ1
000156666 593__ $$aCatalysis$$c2020$$dQ1
000156666 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000156666 700__ $$aMontalvillo-Jiménez, L.
000156666 700__ $$aDíaz-Casado, L.
000156666 700__ $$aCorzana, F.
000156666 700__ $$0(orcid)0000-0002-2202-3460$$aMerino, P.$$uUniversidad de Zaragoza
000156666 700__ $$aCañada, F.J.
000156666 700__ $$aJiménez-Osés, G.
000156666 700__ $$aJiménez-Barbero, J.
000156666 700__ $$aGómez, A.M.
000156666 700__ $$aAsensio, J.L.
000156666 7102_ $$12013$$2765$$aUniversidad de Zaragoza$$bDpto. Química Orgánica$$cÁrea Química Orgánica
000156666 773__ $$g142, 28 (2020), 12501-12514$$pJ. Am. Chem. Soc.$$tJournal of the American Chemical Society$$x0002-7863
000156666 8564_ $$s10180159$$uhttps://zaguan.unizar.es/record/156666/files/texto_completo.pdf$$yVersión publicada
000156666 8564_ $$s3036054$$uhttps://zaguan.unizar.es/record/156666/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000156666 909CO $$ooai:zaguan.unizar.es:156666$$particulos$$pdriver
000156666 951__ $$a2025-10-17-14:14:48
000156666 980__ $$aARTICLE