Synthesis of Macrocyles by Ring Enlargement of 14-Membered Cyclic Imides In the presence of a base, cyclododecanone derivative 2, activated in α-position by an allyloxycarbonyl group, underwent ring enlargement with isocyanates to give 14-membered imides ( Schemes 1-3). Cleavage of the activating group gave new 14-membered imides which could be transformed by further ring-enlargement reactions into new macrocyclic compounds.