The water mediated ring closing in the formose reaction

Jalbout, Abraham F.; Pavanello, Michele; Adamowicz, Ludwik

doi:10.1002/qua.21318

Cited by 4 publications

(3 citation statements)

References 12 publications

(17 reference statements)

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“…The values for formation of S5 ϩ through TS1 were high, but should also be considered as possible mechanisms. Hydronium ion may have dual catalytic properties in these mechanisms [indicated by our recent work on the Nazarov reaction (Jalbout et al, 2007)]; therefore consideration was given for its involvement in the ring-closing mechanism of S1 to yield cyclic product S5 ϩ . This occurs through TS2, which has a forward barrier (⌬H F7 ) of Ϫ7.4 kcal/mol (MP2) and Ϫ6.9 kcal/mol (CCSD (T)//MP2) and an energy of reaction of around Ϫ25 kcal/mol at both the MP2 and CCSD (T)//MP2 levels of theory.…”

Section: H 3 O ϩ Addition Of Dimer To Intermediatementioning

confidence: 99%

Sugar Synthesis from a Gas-Phase Formose Reaction

et al. 2007

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Prebiotic possibilities for the synthesis of interstellar ribose through a protic variant of the formose reaction under gas-phase conditions were studied in the absence of any known catalyst. The ion-molecule reaction products, diose and triose, were sought by mass spectrometry, and relevant masses were observed. Ab initio calculations were used to evaluate protic formose mechanism possibilities. A bilateral theoretical and experimental effort yielded a physical model for glycoaldehyde generation whereby a hydronium cation can mediate formaldehyde dimerization followed by covalent bond formation leading to diose and water. These results advance the possibility that ion-molecule reactions between formaldehyde (CH(2)O) and H(3)O(+) lead to formose reaction products and inform us about potential sugar formation processes in interstellar space.

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Section: H 3 O ϩ Addition Of Dimer To Intermediatementioning

confidence: 99%

Sugar Synthesis from a Gas-Phase Formose Reaction

et al. 2007

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“…For example, Jalbout and co-workers, based on quantum chemical calculations, have argued for the importance of hydrogen bonding to the 3hydroxy group with water in promoting cyclization [50]. Several groups have suggested that, at least in some cases, protic acids play more complicated roles, beyond merely protonating a ketone to generate a 3-hydroxy pentadienyl cation.…”

Section: Potential Dicationic Transition State Structuresmentioning

confidence: 99%

Theoretical Studies on Pentadienyl Cation Electrocyclizations

Tantillo¹

2010

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“…These were also the conditions used in our previous studies on the self-oligomerization of aldehydes. − We are not the first to use computational methods to study some of the reactions in the present system; however, to our knowledge we are the first to systematically provide a broad map of the energy landscape for formaldehyde oligomerization. Previous studies − typically (1) concentrated on isolated reactions of interest, (2) were for gas-phase conditions, and/or (3) were performed semiempirically.…”

Section: Introductionmentioning

confidence: 99%

Mapping the Kinetic and Thermodynamic Landscape of Formaldehyde Oligomerization under Neutral Conditions

et al. 2013

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Density functional theory calculations, including Poisson-Boltzmann implicit solvent and free energy corrections, are applied to study the thermodynamic and kinetic free energy landscape of formaldehyde oligomerization up to the C4 species in aqueous solution at pH 7. Oligomerization via C-O bond formation leads to linear polyoxymethylene (POM) species, which are the most kinetically accessible oligomers and are marginally thermodynamically favored over their oxane ring counterparts. On the other hand, C-C bond formation via aldol reactions leads to sugars that are thermodynamically much more stable in free energy than POM species; however, the barrier to dimerization is very high. Once this initial barrier is traversed, subsequent addition of monomers to generate trimers and tetramers is kinetically more feasible. In the aldol reaction, enolization of the oligomers provides the lowest energy pathway to larger oligomers. Our study provides a baseline free energy map for further study of oligomerization reactions under catalytic conditions, and we discuss how this will lead to a better understanding of complex reaction mixtures with multiple intermediates and products.

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The water mediated ring closing in the formose reaction

Cited by 4 publications

References 12 publications

Sugar Synthesis from a Gas-Phase Formose Reaction

Sugar Synthesis from a Gas-Phase Formose Reaction

Theoretical Studies on Pentadienyl Cation Electrocyclizations

Mapping the Kinetic and Thermodynamic Landscape of Formaldehyde Oligomerization under Neutral Conditions

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