Ruthenium tetraoxides

Chen S., Cao T., and Jin Y., Ruthenium tetraoxide staining technique for transmission electron microscopy of segmented block copoly(ether-ester), Polym. Commun., 28, 314, 1987. 

Epimerization of 50 at C-3 furnished carba-a-DL-allopyranose (60). Stepwise, 0-isopropylidenation of 50 with 2,2-dimethoxypropane afforded compound 56. Ruthenium tetraoxide oxidation of 56 gave the 3-oxo derivative 57, and catalytic hydrogenation over Raney nickel converted 57 into the 3-epimer 58 exclusively. Hydrolysis of 58, and acetylation, provided the pentaacetate 59, which was converted into 60 on hydrolysis. ... 

C. Oxidation with Ruthenium Tetraoxide and Chromate Based... 

Unlike palladium(II), osmium tetraoxide and ruthenium tetraoxide catalyze the dihydroxylation of one or both double bonds of an allene. The osmium tetraoxide-catalyzed dihydroxylation of unsymmetrically substituted allenes 45 can lead to two different a-ketols, 46 and 47, depending on which of the double bonds is oxidized. David et al. studied this reaction using NMO as a stoichiometric oxidant and found good product selectivity in a few cases, but the yields were only moderate (Scheme 17.15) [16]. They showed that the most substituted double bond was oxidized preferably when the bulkiness of the allene substituents did not interfere. 

P. E. Morris, D. E. Kiely, Ruthenium Tetraoxide Phase-Transfer-Promoted Oxidation of Secondary alcohols to Ketones, J. Org. Chem. 52 (1987) 1149-1152. 

Synthesis of D-apiose from 1,2-O-isopropylidene- -L-threofuranose (28) has been accomplished.128 Oxidation with ruthenium tetraoxide... 

Uronic acid degradation of the fully methylated Klebsiella type 47 capsular polysaccharide120 results in a partially methylated polysaccharide having a disaccharide repeating-unit (see Section IV,2, p. 218), in which the hydroxyl groups at C-3 in the L-rhamnose residues are free. Oxidation with ruthenium tetraoxide consequently gave the product 82, which, on treatment with base, followed by... 

Isopropylidene-/ -D-fhra>-pentofuranosyl-2-ulose)adenine (22) was obtained38 from 9-(3,5-0-isopropylidene-/ -D-xylofuranosyl) adenine (21) by oxidation with ruthenium tetraoxide.37... 

In contrast to those results, no useful discrimination between endo and exo hydroxyl groups could be found when employing ruthenium tetraoxide as an oxidant.213 Compounds 4,3, and 5 each affords the diketone 9 exclusively this was isolated as the bis(2,4-dinitrophenylhydrazone). 

Oxidation of l,2 5,6-di-0-isopropylidene-a-D-glucofuranose (217) with ruthenium tetraoxide, using a phase-transfer catalyst, gave the 3-ulose derivative 218, which by further hydrolysis afforded D-n Zw-hexos-3-ulose 219. Benzyltriethylammonium chloride (BTEAC) was used as the catalyst. Using the same oxidant and conveniently derivatized starting materials, a-D-xy/o-hexofuranos-5-ulose, a-D-n Zw-hexofuranos-5-ulose, and /f-L-arabino-hexofuranos-5-ulose derivatives were obtained.436... 

Ruthenium tetraoxide is a powerful oxidant it is more reactive than osmium tetraoxide, and combines explosively with ether or benzene, so that it is generally used as a dilute solution in carbon tetrachloride. Beynon et al.155 first demonstrated the usefulness of this reagent in carbohydrate chemistry by converting methyl 4,6-0-benzylidene-2-deoxy-a-D-n bo- and -D-uraZu rao-hexopyranosides into methyl 4,6-0-benzylidene-2-deoxy-a-D-eryt/zro-hexopyranosid-3-ulose. 

The use of ruthenium tetraoxide as an oxidant in organic chemistry has been reviewed161 and several applications to the carbohydrate field have been described (Ref. 1, p. 1147). 

Oxidation of organic compounds by ruthenium tetraoxide has been reviewed. The oxidation of various types of organic compounds such as alkanes, alkenes, allenes, aromatic rings, alcohols, amines, and sulfides has been discussed The cyclic oxoruthe-nium(VI) diesters that are formed in the initial step of the oxidation of alkenes are considered to be intermediates in the formation of 1,2-diols.70 The development of new and selective oxidative transformations under ruthenium tetroxide catalysis during the past 10 years has been reviewed. The state of research in this field is summarized and a systematic overview of the reactivity and the reaction mode of ruthenium tetroxide is given.71... 

For the ruthenium tetraoxide-catalysed oxidation of propan-l-ol by diperiodato-cuprate(III), hexacyanoferrate(III), periodate, and chloramine-T, a mechanism of direct reaction between Ru(VIII) and propan-l-ol in a slow step to give propanal and Ru(VI) followed by a fast oxidation of Ru(VI) to Ru(VIII) by the co-oxidant has been proposed.73... 

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