Oxidation of cyclooctanol

Moreover, it is possible to selectively oxidize secondary alcohols in the presence of primary alcohols without using any protecting group, as shown in the case of competitive oxidation of cyclooctanol and 1-octanol (Figure 13.3). 

The Jones method is rapid and the yields high. The main limitation is the low solvent power of acetone. However, the method was used successfully by Eisen-braun for oxidation of cyclooctanol to cyclooctanone on a fairly large scale. 

Scheme 8.3. A possible pathway for the oxidation of cyclooctanol to cyclooctanone by the Dess-Martin triacetoxyperiodinane [l,l,l-triacetoxy-l,l-dihydro-l,2-benziodoxol-3(l,H)-one].

As chromic acid oxidizes the alcohol to the ketone, chromium is reduced from the +6 oxidation state (H2Cr04) to the +3 oxidation state (Cr +). Chromic acid oxidations of secondary alcohols generally give ketones in excellent yields if the temperature is controlled. A specific example is the oxidation of cyclooctanol to cyclooctanone ... 

Suberic Acid. This acid is not produced commercially at this time. However, small quantities of high purity (98%) can be obtained from chemical supply houses. If a demand developed for suberic acid, the most economical method for its preparation would probably be based on one analogous to that developed for adipic and dodecanedioic acids air oxidation of cyclooctane to a mixture of cyclooctanone and cyclooctanol. This mixture is then further oxidized with nitric acid to give suberic acid (37). 

Chlorination and oxidation. This reagent is stable and easy to handle. It can be used to introduce chlorine atoms to C-2 of 2-substituted 1,3-dioxolanes, the a-position of aldehydes besides alkenes and alkynes. Oxidation of alcohols such as benzyl alcohol and cyclooctanol in MeCN requires pyridine-DABCO (4 1) as acid scavenger. 

Oxidation of alcohols or carbonyl compounds (general method). Synthesis of 2-cyclooctenone.1 To a solution of cyclooctanol 1 (1 mmol) in fluorobenzene DMSO (2 1, 0.1 M) was added 2.2 equiv of IBX and the solution was heated to 55-65 °C (or to 85 °C for synthesis of 3). The reaction was monitored by TLC. Dilution with Et20 and usual work up followed by flash chromatography afforded 2-cyclooctenone 2 in 77% yield. 

In this area, a significant result is the selective conversion of cycloalkanes to the corresponding ketones. The oxidation of cyclooctane by tert-butylhydroperoxide (tBHP) was performed with Ru colloids in biphasic water/cyclooctane media, leading to the main formation of cyclooctanol and cyclooctanone (Scheme 11.12) [88, 89]. Cyclooctanone is always the major product. Mechanistic studies with inhibition and kinetic reactions suggest ruthenium 0x0 species are the most probable catalysts for ketonisation. The catalyst could be recycled without any loss of activity. Finally, model extension experiments to other cycloalkanes are also investigated. 

There is a reaction that converts a ketone carbonyl (C=0) to an alcohol unit (CH-OH) called a reduction. The conversion of the alcohol back to the ketone is called an oxidation. It is known that reduction of cyclooctanone to cyclooctanol (draw both structures) is relatively difficult, whereas the oxidation of the alcohol to the ketone is relatively easy. Explain why. 

The oxidation of aliphatic primary and cyclic alcohols " to the corresponding aldehydes and ketones by quinolinium chlorochromate (QCC) is first order each in QCC, alcohol, and H+ a mechanism involving rate-limiting hydride ion transfer has been proposed. The relative reactivity for the cyclic alcohols (cyclohexanol < cyclopen-tanol < cycloheptanol < cyclooctanol) is explained on the basis of I-strain theory. The oxidation of mandelic, lactic, and glycolic acids by QCC is first order with respect to oxidant and H+ and fractional order with respect to substrate. ... 

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