Ring Cleavage of Cyclic a-Nitro Ketones Retro-Acylation

One-pot syntheses of 1,4-diketones, y-oxoaldehydes, y-ketoesters, and co-oxoalkanoates have been reported by bond cleavage of cyclic a-nitroketones with KOH in methanol and subsequent Nef reaction (Section 6.1) with KMn04 (Eq. 5.16).31 

Regioselective reduction of 2-nitrocycloalkanones with sodium borohydride affords co-nitro alcohols. This reaction is applied to the synthesis of spiroketals as shown in Eq. 5.17, in which spiro[4,5]- and spiro[4,6]ketal systems are obtained in good yields.32 

Oxidative cleavage of 2-nitrocyclohexanones gives a,co-dicarboxylic acids or their esters, as shown in Eq. 5.18.33 

The reaction of a-nitrocycloalkanones with an aqueous solution of formaldehyde in the presence of potassium carbonate affords 2-nitro-l,3-diol-co-alkanoic acids (Eq. 5.21).36 

Ring enlargement of cc-nitrocycloalkanones has been extensively used for the synthesis of macrocyclic compounds, as exemplified in Eq. 5.22.37 

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