Cyclooctanone reduction

The reductive dehalogenation predominates in the photoinduced reactions of 32 with 3-pentanone, 2-methyl-3-pentanone, and 2,4-dimethyl-3-pentanone. Although, substitution is favored over reduction in all of the reactions of 32 with cyclic ketone enolates, a competing reduction is responsible for the lower yields observed with cyclopentanone and cyclohexanone compared to cyclooctanone (Scheme 10.59) [73]. 

Indeed, cyclobutanones constitute challenging synthetic intermediates for a whole host of applications including cyclopentanone, cyclohexanone and cyclooctanone formation, olefin and diene synthesis, geminal alkylation, reductive acylation, among others,... (vide infra). 

Whereas cyclooctanone undergoes Wolff-Kishner reduction to give exclusively cyclooctane, reduction under Clemmensen conditions affords bicyclo[3.3.0]octane as well.99 This finding again points up the risks which one takes in maintaining... 

The procedure has been shown applicable to the reductive amination of cyclohepta-none, cyclooctanone, acetophenone, norhomanonc, and benzaldehyde. Amines used include ammonia, methylamine, dimethylamine, morpholine, aniline, and hydroxyl-... 

Larpent and Patin studied the oxidation of saturated hydrocarbons using reverse microemulsions of iron(III) chloride and hydrogen peroxide in the hydrocarbon. They obtained only low concentrations of oxidized products (0.030 M of cyclooctanone in cyclooctane) with a low efficiency of 7-8%. We were able to obtain similar results in the cyclohexane oxidation a 0.020 M solution of one + ol (1 1 ratio), with an efficiency with respect to hydrogen peroxide of 5%, was easily prepared. To increase the concentration of oxidized products in this system seems to be difficult, as the phase diagram changes with higher concentrations of the reagents, which causes further reduction of the efficiency. 

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. 

Many ketones such as 2-methylcyclopentanone, 2-heptanone, 3-methyl-2-butanone, camphor, cyclooctanone, benzophenone,p-chloroacetophenone, 3,3-dimethyl-2-butanone, and 2-methyl-3-pentanone do not show either first-order or three-halves-order kinetics cleanly. Apparently, in these cases, the rates of dissociation of (9-BBN)2 and reduction by 9-BBN monomer are comparable, which leads to complex kinetic behavior. 

The data show that reduction of carbonyls with 9-BBN is less susceptible to steric effects than is sodium borohydride, in spite of the bulky nature of the former reagent. For example, cyclooctanone is reduced by 9-BBN by a factor of 50 slower than cyclohexanone. Whereas the factor is as much as 2,050 for reduction with sodium borohydride [3c]. 

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