A synthetic equivalent is supposed to be a reagent whose structure, when in the final product, gives the appearance of having come from another starting reagent when as a starting material it had a different structural origin.
I believe an example is the ethyl acetoacetate ion and acetone enolate.
However I don't really understand why the two would be called synthetic equivalents. Doesn't the acetoacetate have the extra ester group attached to it in the final product?
Thanks