Large-Scale Oxidations of Alcohols, Carbohydrates and Diols

7 Large-Scale Oxidations of Alcohols, Carbohydrates and Diols 

Some syntheses (using 1 g of substrate) are explicitly described in the literature selected oxidations of carbohydrates are included in the first column of Table 2.3. 

Substrates include benzyl (2 g) and cinnamyl (2.7 g) alcohols to acids cyclopentanol (1 g), benzhydrol (3.9 g), benzoin (4 g), pantolactone (2.6 g) to ketones (RuCy TCCA/( Bu N)Br/aq. Kj(C03)/CH3CN) (Fig. 2.14) [25] [[2-[2-hydroxypropyl) amino]-l,2-dioxoethyl]amino]acetic acid ethyl ester (6.21 kg) to [(l,2-dioxo-2-oxopropyl)amino]ethyl)amino] acetic acid ethyl ester, part of the industrial-scale synthesis of thrombin inhibitor (RuCyaq. Na(BrOj)/CH3CN) [166] (H-)-dihydroc-holesterol (8 g) to cholest-3-one (RuO /aq. K(10 )/(BTEAC)/CHCl3) [308]  

5- ero,6-endb-dihydroxy-bicyclo[2.2.1]-heptane-2-ent/o-carboxylic acid lactone (5 g) (RuCyaq. Na(10 )/CCl ) [203] ethyl 3-hydroxy-cyclobutane-carboxylate (7 g) to ketone (RuCyaq. Na(10yCCy (Tables 2.1 and 2.2) [34] cyclohexanol (1.5 g) (stoich. RuO /H O) [1]. 

Although these encompass primary and secondary alcohols they are considered here in a separate section since so much work has been done in the area, using RuO as the oxidant. In most cases it was used for oxidation of secondary alcohol groups in carbohydrates to ketones, but its first application, albeit stoicheiometrically as RuOy CCy was for the conversion of a secondary alcohol unit in l,2 5,6-di-0-isopropy-lidene-a-D-glucofuranose to the D-nfeo-hexofuranos-3-ulose (Fig. 2.13) [310]. There are early but illuminating reviews on carbohydrate oxidations by RuO [18, 311]. 

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