- Hydrogen-Bonding Interactions in the Ley–Griffith Oxidation: Practical Considerations for the Synthetic Chemist
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The Ley–Griffith oxidation, which is catalyzed by tetra-n-propylammonium perruthenate (TPAP, nPr4N[RuO4]), is a popular method for not only controlled oxidation of primary alcohols to aldehydes, but also a host of other synthetically useful transformations. While the fundamental reaction mechanism has recently been elucidated, several key hydrogen-bonding interactions between the reagents were implicated but not investigated. Herein the prevalence of H-bonding between the co-oxidant N-methylmorpholine N-oxide (NMO), the alcohol substrate, water and the perruthenate catalyst is established. These observations help to rationalize the importance of drying the reagents and lead to several practical suggestions.
- Moore, Peter W.,Zerk, Timothy J.,Burns, Jed M.,Bernhardt, Paul V.,Williams, Craig M.
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- Ranking Oxidant Sensitiveness: A Guide for Synthetic Utility
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Common oxidants used in chemical synthesis, including newly developed perruthenates, were evaluated in the context of understanding (and better appreciating) the sensitiveness and associated potential hazards of these reagents. Analysis using sealed cell differential scanning calorimetry (scDSC) facilitated Yoshida correlations, which were compared to impact sensitiveness and electrostatic discharge experiments (ESD), that enabled sensitiveness ranking. Methyltriphenylphoshonium perruthenate (MTP3, 8), isoamyltriphenylphosphonium perruthenate (ATP3, 7) and tetraphenylphosphonium perruthenate (TP3, 9) were found to be the most sensitive followed by 2-iodoxybenzoic acid (IBX, 2) and benzoyl peroxide (BPO, 10), whereas the most benign were observed to be Oxone (12), manganese dioxide (MnO2, 13), and N-bromosuccinimide (NBS, 17).
- Dallaston, Madeleine A.,Bettencourt, Christian J.,Chow, Sharon,Gebhardt, Joshua,Spangler, Jordan,Johnston, Martin R.,Wall, Craig,Brusnahan, Jason S.,Williams, Craig M.
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- N -Oxides rescue Ru(v) in catalytic Griffith-Ley (TPAP) alcohol oxidations
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The redox and ligand exchange reactions of oxido-ruthenium complexes are central to the function of the Sharpless and Griffith-Ley one-step alcohol oxidation protocols. However, their mechanisms have not been elucidated. Cyclic voltammetry and UV-vis spec
- Zerk, Timothy J.,Moore, Peter W.,Williams, Craig M.,Bernhardt, Paul V.
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- Preparation method of tetra-n-propyl ammonium perruthenium
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The invention discloses a preparation method of tetra-n-propyl ammonium perruthenium, which comprises the following steps: (1) uniformly mixing and stirring anhydrous sodium carbonate, sodium bromateand water, and stirring at 20-40 DEG C for 1-2 hours; (2) adding ruthenium chloride hydrate into the reaction system in the step (1), and reacting at 20-40 DEG C for 5-10h; (3) dropwise adding 25wt% of tetrapropylammonium hydroxide into the reaction system in the step (2), and reacting for 5-10h at the temperature of 20-30 DEG C after dropwise adding; and (4) adding an extracting solution into thereaction system for extraction, concentrating under normal pressure until no liquid is discharged, adjusting the temperature to 20-30 DEG C, adding a pulping solvent, pulping, filtering, and carryingout vacuum drying on a filter cake, thereby obtaining the product. Wherein the extracting solution is dichloroethane or chloroform; wherein the pulping solvent is alkane or petroleum ether. The method provided by the invention is mild in reaction condition, simple and convenient in technological operation, small in ligand usage amount and high in comprehensive yield, the purity of the prepared tetrapropylammonium hydroxide is greater than or equal to 99%, the yield is greater than or equal to 99%, and high-efficiency utilization of the technology is realized.
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Paragraph 0011-0018
(2021/02/06)
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- ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
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The Ley–Griffith tetra-n-propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
- Moore, Peter W.,Read, Christopher D. G.,Bernhardt, Paul V.,Williams, Craig M.
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supporting information
p. 4556 - 4561
(2018/03/13)
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- Studies on transition-metal oxo and nitrido complexes. 13. Perruthenate and ruthenate anions as catalytic organic oxidants
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The [RuO4]- ion can be generated in aqueous base at pH 11 from aquated ruthenium trichloride with excess bromate, and this reagent will catalytically oxidize primary alcohols, activated alkyl halides, aldehydes, 1,2-diols, and nitroalkanes to carboxylic acids, while secondary alcohols and secondary halides are oxidized to ketones, bromate being the cooxidant. These oxidations are compared with those effected catalytically by trans-[Ru(OH)2O3]2- in aqueous base at pH 14 with persulfate as cooxidant. A new preparation for organic-soluble salts of [RuO4]- avoiding the use of RuO4 is described.
- Bailey, Alan J.,Griffith, William P.,Mostafa, Sahar I.,Sherwood, Paul A.
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p. 268 - 271
(2008/10/08)
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- Preparation and Use of Tetra-n-butylammonium Per-ruthenate (TBAP reagent) and Tetra-n-propylammonium Per-ruthenate (TPAP reagent) as New Catalytic Oxidants for Alcohols
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Tetra-n-butylammonium per-ruthenate (Bun4N)(RuO4) and tetra-n-propylammonium per-ruthenate (Prn4N)(RuO4), with N-methylmorpholine N-oxide, function as mild catalitic oxidants for the high yield conversion of alcohols to aldehydes and ketones and are competitive with more conventional reagents.
- Griffith, William P.,Ley, Steven V.,Whitcombe, Gwynne P.,White, Andrew D.
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p. 1625 - 1627
(2007/10/02)
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