Decanone, reduction

The acyloin reaction is so useful for making medium and large rings that cyclic ketones are often made this way. Reduction of acyloin (32) with zinc in acid solution or HI removes the unwanted hydroxyl group to give cyclo-decanone (33) in good yield. 

This beneficial effect was attributed to rate enhancements of reduction processes. With benzoic acid, total degradation of the ring to CO2 occurred and the detection of salycilic acid suggested the intervention of 0H° radicals (56). These radicals were also proposed to explain the oxidation of n-Cx alkanes (x = 6,7,9,10) and of cyclohexane in 1 1 vol. water ydrocarbon two-phase mixtures over 10 wt °l Pt/Ti02 Traces of alcohols (and of 2-, 4-, 5-decanone with decane) were detected. No transformation occurred without O2 and in the absence of H2O the rate was substantially decreased. The role of Pt was attributed to a greater ease of oxygen reduction however the oxidation rate was only decreased by a factor of about 1.5 without Pt (59). 

Zinc dust-mineral acid. Reduction. For the reduction of sebacoin to cyclo-decanone, Cope and co-workers added hydrochloric acid slowly to a stirred... 

This reaction was reinvestigated with cw-l,7-dimethyltricyclo[4.4.0.0 ]decan-3-one (30) as a model compound. The reduction with lithium to the spiro[4.5]decanone product occurred predominantly with inversion of configuration at the jS-carbon atom. However, the ratio of inversion to retention depends on the reaction temperature and the amount of alcohol added. Both higher temperature and more alcohol increased the proportion of the retention product. 

Clemmensen500 has described the preparation of H-undecane from 2-un-decanone as an example of the reduction of aliphatic ketones to straight-chain hydrocarbons ... 

Muscone is then prepared by the following sequence reduction to the aUyl alcohol, ozonolysis of the double bond, Wolff-Kishner reduction of both carbonyl groups, and Jones oxidation. The overall yield is around 40 % based on cydodo-decanone. 

Nine- and Ten-membered Rings.—Reduction of 1-bromo-cw-cyclononene and either l-bromo-trans,ds- or l-bromo-ds,cis-cyclonona-l,5-diene with sodium in liquid ammonia gave ds-cyclononene and cis,ds-cyclonona-1,5-diene, respectively." Thermolysis of bicyclo[7,l,0]deca-l,7-diene and bicyclo[8,l,0]undeca-1,8-diene gives 3-methylene-cis,ds-cyclonona-l,4-diene and a mixture of 3-methylene-ds,ds-cyclo-deca-1,4-diene and 10-methylenebicyclo[5,3,0]dec-8-ene, respectively. Cyclo-nonanone tosylhydrazone gives ds-cyclononene exclusively when treated with methyl or n-butyl lithium, whereas both cis- and trans-cyclodecenes are obtained from cyclo-decanone tosylhydrazone. The cis.trans olefin ratio in this case is solvent dependent probably, because of the effect of solvent on the tosylhydrazone conformation." ... 

Further investigations of the approach to spiro[4,5]decanones based on reductive cleavages of the cyclopropane rings in tricyclo[4,4,0,0, ]decanones have been forthcoming/ and the potential for oxycyclopropane derivatives in synthesis is very well demonstrated in a synthesis of j8-vetivone (230) from the /3-oxycyclopropyl ketone (229)/ ... 

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