Nitro-stabilized anion

The nitro group is one of the best activating groups for conjugate addition as it almost never gives direct addition. Even the weakly nucleophilic acetate ion will react as the nitro-stabilized anion is very stable indeed. 

In conclusion, C-C bond formation on carbohydrates has absorbed lots of widely used methods from general synthetic organic chemistry. Typical among these methods are intramolecular alkylation and intramolecular condensation of aldehyde with enolates, phosphonates, and nitro-stabilized anions. Metal-mediated radical reactions, cycloadditions, and rearrangements have also been applied frequently. 

Nitro-stabilized anions also undergo additions to aldehydes, ketones, and electrophilic alkenes these reactions appear in Chapters 27 and 29. 

The nitro group can be converted into other useful functional groups following conjugate addition. Reduction gives primary amines while hydrolysis reveals ketones. The hydrolysis is known as the Nef reaction and used to be achieved by formation of the nitro-stabilized anion with a base such as sodium hydroxide followed by hydrolysis with sulfuric acid. These conditions are rather unforgiving for many substrates (and products) so milder methods have been developed. One of these involves ozonolysis of the nitro enolate at low temperature rather than treatment with acid. 

In recent work Kende and his coworkers have explored intramolecular oxidative coupling between phenolate and enolate, rather than between two phenolates. This proved a viable process for certain carbonyl enolates, and for nitro-stabilized anions, llius potassium ferricyanide oxidations of the indandione... 

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