1,2-dioxoles and 1,2-oxathioles

Developments in the chemistry of five-membered ring heterocycles containing two adjacent oxygens or one oxygen and one sulfur in the period 2008–2020 are reviewed. Application of theoretical and structural methods to these compounds is described including X-ray structure determination and NMR. The major reactions of 1,2-dioxolanes and 1,2-oxathiole systems are discussed. Methods for the synthesis of all the compounds are systematically covered. There has been significant activity in developing new synthetic methods to 1,2-dioxolanes driven both by the presence of this heterocycle in some antitumour natural products and the promising antimalarial activity shown by many synthetic dioxolanes. The chemistry of simple 1,2-oxathiole S,S-dioxides has also been expanded.