Cycloalkanes, from cyclic ketones

Strain energies (kcal mol 1) of cyclic ketones and cycloalkenes relative to cycloalkanes from force-field calculations... 

Olefins may be converted in high yield to a-ahtoroketones by treatment with chromyl chloride in acetone. a-Carboxyketones, generally relatively inaccessible, can be prepared by treatment of ketones with lithium 4-methyl-2,6-di-tert-butylphenoxide and carbon dioxide. Cyclic ketones result from ring expansion of methylene cycloalkanes with cyanogen azide followed by hydrolysis, a procedure which complements the standard diazo-methane-ketone approach. Functionalized cis-bicyclic ketones can be synthesized by haloketal cyclizatlon followed by hydrolysis. ... 

More complex products are obtained from cyclizations in which the oxidizable functionality and the alkene are present in the same molecule. y9-Keto esters have been used extensively for Mn(III)-based oxidative cyclizations and react with Mn(OAc)3 at room temperature or slightly above [4, 10, 11, 15], They may be cyclic or acyclic and may be a-unsubstituted or may contain an a-alkyl or chloro substituent. Cycloalkanones are formed if the unsaturated chain is attached to the ketone. y-Lactones are formed from allylic acetoacetates [10, 11]. Less acidic /3-keto amides have recently been used for the formation of lactams or cycloalkanones [37]. Malonic esters have also been widely used and form radicals at 60-80 °C. Cycloalkanes are formed if an unsaturated chain is attached to the a-position. y-Lactones are formed from allylic malonates [10, 11]. yff-Diketones have been used with some success for cyclizations to both alkenes and aromatic rings [10, 11]. Other acidic carbonyl compounds such as fi-keto acids, /3-keto sulfoxides, j8-keto sulfones, and P-nitro ketones have seen limited use [10, 11]. We have recently found that oxidative cyclizations of unsaturated ketones can be carried out in high yield in acetic acid at 80 °C if the ketone selectively enolizes to one side and the product cannot enolize... 

---