Oxidation vicinal diols

Vicinal diol is oxidized to the two corresponding carbonyl compounds using Pb(OAc)4, lead tetraacetate (LTA). 

Dihydroxylation, the addition of two hydroxy groups across a C = C bond, converts fluorinated alkenes into different products depending on the presence or absence of a fluorine atom at the hydroxylated carbon. Partially fluorinated alkenes with vicinal hydrogen atoms attached to the C = C bond can be hydroxylated to vicinal diols. When the reaction is performed with a sufficiently strong oxidizing agent, the initially formed diols are oxidized to vicinal diketones as the end products. 

Vicinal diols have been cleaved with molecular oxygen using a ruthenium pyrochlore oxide catalyst. Cyclohexane-1,2-diol was oxidized to adipic acid in 72% yield with this catalyst system (Eqn. 21.38). Cyclohexanone was also converted to adipic acid under these conditions. 5... 

In the final stages of the total synthesis of (+)-cephalotaxine by M.E. Kuehne et al., a tetracyclic c/s-vicinal diol was oxidized to the a-diketone. Using PCC, pyridine/SOs or the Swem protocol did not yield the desired product. However, by applying the Corey-Kim protocol, NCS-DMS in dichloromethane at -42 °C, afforded the diketone in 89% yield. 

Diols, meso-, enzymic oxidation to y-lactones, 63, 14 DIOLS, VICINAL, EPOXIDES FROM, 63, 140 m-D1oxane, 2-(2-bromoethyD- [33884-43-4], 62, 148... 

Vicinal diols undergo oxidative cleavage. There is no apparent steric limitation as both cis- and fra s-cycloalkane-l,2-diols are susceptible to cleavage. However, under certain conditions a-hydroxy ketones may be oxidized without breaking the C-C bond. ... 

While DDO has been little used for the oxidation of simple alcohols, it has found application in useful conversions of vicinal diols. The oxidation of tertiary-secondary diols to a-hydroxy ketones occurs without the usual problem of oxidative cleavage between the two functions (eq 16). DDO has also been used to convert appropriate optically active diols selectively into a-hydroxy ketones of high optical purity for example, see (eq 17). ... 

The next task undertaken was the creation of the diequatorial vicinal diol. Hydroboration/oxidation of C4 would occur predictably at the electron-rich enol silyl ether double bond, and indeed, compound C6 was obtained in 71% as the only diastereomer. The rationalization for this remarkable stereocontrol was based on the assumption that the transition state was as shown in C5, where the amine-bearing appendage assumed a pseudo axial orientation in order to reduce strain [41]. This results in a flattened boat, as shown, and the preferred approach by borane is therefore anti to the pendant C-10 substituent. 

Lead tetraacetate-2,7-dichlorofluorescein (A) lead tetraacetate (saturated solution) in glacial acetic acid (B) 2,7-dichlorofluorescein in water (1%, m/v, or lower, down to 0.2%, if background interferes with detection) A and B are mixed 1 1 (v/v), then toluene (19 1, v/v) is added Plate is dipped in reagent for 10s, then heated at 100°C for 3 min All carbohydrates with vicinal diol groups, oxidized by lead tetraacetate, are detected fluorimetric scanning (excitation 313nm, emission 366 nm) 50-100pmol... 

A reaction characteristic of vicinal diols is their oxidative cleavage on treatment with periodic acid (HIO4) The carbon-carbon bond of the vicinal diol unit is broken and two carbonyl groups result Periodic acid is reduced to iodic acid (HIO3)... 

Periodic acid oxidation (Section 15 12) finds extensive use as an analytical method m carbohydrate chemistry Structural information is obtained by measuring the number of equivalents of periodic acid that react with a given compound and by identifying the reaction products A vicinal diol consumes one equivalent of penodate and is cleaved to two carbonyl compounds... 

The reaction is based, on the one hand, on the oxidative cleavage of vicinal diols by lead(IV) acetate and, on the other hand, on the reaction of dichlorofluorescein with lead(IV) acetate to yield a nonfluorescent oxidation product. The dichlorofluorescein only maintains its fluorescence in the chromatogram zones where the lead(IV) acetate has been consumed by the glycol cleavage reaction [1],... 

Although lead tetraacetate can attack many polar and nonpolar functions in the steroid molecule, its greatest reactivity is towards vicinal diols. These diols are generally cleaved so rapidly under stoichiometric conditions that other alcohol functions in the molecule need not be protected. Thus lead tetraacetate in acetic acid at room temperature splits the 17a,20-diol group in (9) to yield the 17-ketone (10), the allylic A -3jS-alcohol remaining intact during this oxidation. Since lead tetraacetate is solublein many anhydrous... 

PerfluoroaUcenes are converted to vicinal diols when no fluonne atom is present at the double bond Configurational isomers of perfluoroalkenes [29] (equations 20 and 21) are oxidized stereospecifically Perfluorbicyclo[4 3 0]non-1(6) ene gives the corresponding 1,6 diol m a 24% yield upon oxidation with potassium permanganate at 18 °C for 1 h [29]... 

---