The above retrosynthetic step would be a more sensible choice than the one shown below for two main reasons. For one, the nucleophile formed by deprotonation of B is a doubly stabilized anion with the negative charged delocalized into both the ketone and the ester. In addition, the retrosynthetic pathway outlined in figure 4.3 (above) offers greater simplification -- to two targets with recognizable structural features. B is a beta keto ester and C is an alpha beta unsaturated ketone, and we have learned methods for synthesizing both of these. Back