The strategies for the synthesis of naturally occurring ten-membered-ring lactones, which are the most abundant of the medium-ring lactones, are discussed. According to their structures and/or biosynthesis, the molecules are classified in monocyclic polyketides, monocyclic oxylipins, aliphatic bicyclic and aromatic bicyclic lactones. In each subsection, the lactones are presented in chronological order of their isolation. Representative complex systems bearing multiple functionalities in addition to the lactone moiety, as well as a selection of recent synthetic approaches to non-natural medium-ring lactones, are briefly presented. 1 Introduction 2 Monocyclic Ten-Membered-Ring Lactones 2.1 Polyketides 2.2 Oxylipins 3 Bicyclic Ten-Membered-Ring Lactones 3.1 Aliphatic 3.2 Aromatic 4 Complex Ten-Membered-Ring Lactones 5 Non-natural Lactones: Selected Synthetic Approaches 6 Conclusion

The natural occurrence, biological activities and synthetic approaches to natural eight-, nine-, and eleven-membered lactones is reviewed. These medium ring lactones are grouped according to ring size, and their syntheses are discussed. The structures of some natural products early identified as medium-ring lactones were revised after total synthesis.FAPESPCNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

This review summarizes the papers dealing with the synthesis of mintlactone and isomintlactone, two natural monoterpenic lactones found in mint oils.