Santos, Clementina M.M.Silva, Artur M.S.2026-05-082026-05-082025Santos, Clementina M.M. Silva, Artur M.S. (2025). Six-membered ring systems: With O and/or S atoms. In Progress in Heterocyclic Chemistry. Amsterdam: Elvisevier. p. 463-538. ISBN 978-0-443-44354-1978-0-443-44354-10959-6380http://hdl.handle.net/10198/36596This chapter covers the most relevant trasformations for the synthesis of O- and S-6-membered heterocycles, published in 2024. This personal overview is focused on the new achievements made on the synthesis of several natural compounds, specific reactions and reagents for the preparation of natural and synthetic pyrans, chromenes and chromans, isochromenes and isochromans, pyranones, coumarins and isocoumarins, chromones and chromanones, xanthenes and xanthones, thiopyrans and analogues, dioxanes, trioxanes, tetraoxanes, dithiins, and also oxathianes.eng(Thio)PyransBenzopyran derivativesChromonesCoumarinsDioxanesDithiinsOxathianesPyranonesXanthenesXanthonesbook part10.1016/B978-0-443-44354-1.00009-7