Santos, Clementina M.M.Silva, Artur2022-08-022022-08-022021Santos, Clementina M.M.; Silva, Artur (2021). Six-membered ring systems: with O and/or S atoms. In Progress in Heterocyclic Chemistry. ISSN 0959-6380. 33, p. 473-532.0959-6380http://hdl.handle.net/10198/25800A large variety of publications have emerged in 2020 involving O- and S-six-membered ring systems. Special emphasis is given to the large number of reviews that have been published during this year, perhaps because the pandemic situation caused by COVID-19 forced scientists around the world to leave their work in the laboratory and concentrate their efforts on the compilation of reviews. Hereinafter, we provide a personal overview of the most important developengThio)pyransBenzopyransChromonesCoumarinsDioxanesbook part10.1016/B978-0-323-98410-2.00015-1