For 10 points, name this reaction that produces beta-ketoesters, a condensation named for a German.
Among the enzymes that can catalyze biological versions of this reaction is polyketide synthase. In the mevalonate pathway, two reactions of this sort are performed on acetyl-CoA in order to form HMG-CoA. A modification of this reaction that uses succinic acid derivatives is named for Stobbe, and a classic laboratory demonstration of it is a synthesis of acetoacetate. An intermolecular form of this reaction creates (*) five or six-member rings and is named for Dieckmann. This reaction, which often uses the harpoon base LDA, begins with the deprotonation of the alpha carbon of an ester, which then attacks the carbonyl group of another ester. For 10 points, name this reaction that produces beta-ketoesters, a condensation named for a German.
Among the enzymes that can catalyze biological versions of this reaction is polyketide synthase.
Claisen condensation [prompt on "Claisen", there's more than one reaction named for him]