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Creators/Authors contains: "Kwok, Ryan W"

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  1. ; ; ; (, Molecules)
    Using methods of DFT, we investigated the effect of electron withdrawing and electron donating groups on the relative stability of tentative glycosyl donor reaction intermediates. The calculation shows that by changing the stereoelectronic properties of the protecting group, we can influence the stability of the dioxolenium type of intermediates by up to 10 kcal mol−1, and that by increasing nucleophillicity of the 4-O-Bz group, the dioxolenium intermediate becomes more stable than a triflate–donor pair. We exploited this mechanism to design galactosyl donors with custom protecting groups on O2 and O4, and investigated the outcome of the reaction with cyclohexanol. The reaction showed no change in the product distribution, which suggests that the neighboring group participation takes precedence over remote group participation due to kinetic barriers. 
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    Free, publicly-accessible full text available January 1, 2026
  2. ; ; ; ; ; (, RSC Mechanochemistry)
    Mechanical activation of reactions can reduce significantly the amounts of solvent and energy required to form covalent organic bonds. 
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  3. ; ; ; (, Organic Letters)
    A combination of DFT calculations and experiments is used to describe how the selection of a promoter can control the stereochemical outcome of glycosylation reactions with the deoxy sugar saccharosamine. Depending on the promoter, either α- or β-linked reactive intermediates are formed. These studies show that differential modes of activation lead to the formation of distinct intermediates that undergo highly selective reactions through an SN2-like mechanism. 
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  4. ; ; ; ; ; ; ; ; ; (, Science)
    A modified atomic force microscope is used to probe activation effects that may accelerate reactions in a ball mill. 
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