Dieckmann reaction 3-heteroatoms

The intramolecular version of the Claisen ester condensation is sometimes known as the Dieckmann reaction, It provides an excellent route to heterocyclic ketones (cyclic ketones with heteroatoms in the ring very important in. . 

The ability of the Dieckmann reaction to tolerate heteroatoms in the ring-forming sequence of atoms has led to its extensive use in heterocyclic synthesis. Many complex systems containing heterocyclic rings have been prepared by routes that include this reaction, and twth aromatic and alicyclic rings have been constructed. A variety of bases and solvents have been employed and representative examples are illustrated in Scheme 45. 

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