Nitroalkanes are superb at conjugate addition

The enolate ion intermediate is now much more basic than the anion of the nitro compound so it removes a proton from the nitro compound and provides another molecule of anion for the second 

The acidifying effect of the nitro group is so profound that very mild bases can be used to catalyse the reaction. This enables selective removal of the proton next to the nitro group and helps to avoid side-reactions involving aldol condensations of the carbonyl component. Common examples include amines, quaternary ammonium hydroxides, and fluorides. Even basic alumina is sufficient to catalyse virtually quantitative addition of this benzylic nitroalkane to cyclohexenone at room temperature  

Anions of nitro compounds form quaternary centres with ease in additions to a,p-unsaturated mono- and diesters. The difference between acidity of the protons next to a nitro group and those next to the esters in the products coinbined with the very mild basic conditions ensure that no unwanted Claisen condensations occur. 

Nitro methane readily undergoes multiple conjugate additions under more forcing conditions with excess ester. 

Nitroalkane conjugate addition can be combined with other reactions 

Always draw out the nitro group In full when using It In mechanisms. 

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