Knoevenagel reaction synthetic utility

The synthesis of 2,2-dimethylsuccinic acid (Expt 5.135) provides a further variant of the synthetic utility of the Knoevenagel-Michael reaction sequence. Ketones (e.g. acetone) do not readily undergo Knoevenagel reactions with malonic esters, but will condense readily in the presence of secondary amines with the more reactive ethyl cyanoacetate to give an a, /f-unsaturated cyanoester (e.g. 15). When treated with ethanolic potassium cyanide the cyanoester (15) undergoes addition of cyanide ion in the Michael manner to give a dicyanoester (16) which on hydrolysis and decarboxylation affords 2,2-dimethylsuccinic acid. 

One of the first supported organic bases utilized as catalysts for synthetic purposes was the propylamine tethered onto amorphous silica employed to perform the Knoevenagel reaction [9]. After this early study a growing number of papers has been published describing the preparation of different organic bases anchored to solid supports including guanidines (10. ... 

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