Ethyl 2-methylpropanoate, Claisen ester

Unless the p keto ester can form a stable anion by deprotonation as m step 4 of Figure 21 1 the Claisen condensation product is present m only trace amounts at equi librium Ethyl 2 methylpropanoate for example does not give any of its condensation product under the customary conditions of the Claisen condensation... 

An example of an ester that does not react in a normal Claisen condensation, because it has only one a hydrogen, is ethyl 2-methylpropanoate ... 

---