A variation of the Claisen condensation, the Dieckmann condensation, where a molecule with two ester groups reacts intramolecularly, forming a cyclic ?-keto ester. In this case, the ring formed must not be strained, usually a 5- or 6-membered ring.
Click this LINK to visit the original image and attribution information. Right click on the image to save the 800px teaching JPEG.
