Acids Cleavable by Bases or Nucleophiles

Most of the reagents required for the saponification of resin-bound esters are, unfortunately, non-volatile, and purification of the products is generally necessary. This is probably the main reason for the scarcity of examples of cleavage by saponification as compared with other methods of cleavage. 

The type of support chosen can have an impact on the facility with which nucleophilic cleavage takes place. Polystyrene, a very hydrophobic support, is difficult to perfuse with small ions such as hydroxide, and for this reason the saponification of poly-styrene-bound esters usually proceeds more slowly than the corresponding solution reaction. Tentagel, polyacrylamides, or other more hydrophilic supports are generally a better choice if saponifications or other reactions involving small ions are to be performed. 

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