New Aspects of Dithio and Thiono Esters

Publisher Website
Google Scholar
Abstract
The field of dithio and thiono esters is expanding rapidly. Therefore emphasis is layed mainly on results obtained by the research group of the author. In agreement with theoretical considerations thiono esters are always more stable than dithio esters. In the preparation of dithio and thiono esters by thiolysis slightly acidic conditions were found to be essential. The CH-acidity at the α-carbon of dithio and thiono esters with pK values about 12 is comparable to that of classical aCH-acidic compounds such as acetoacetic ester. Dithiono and tetrathio malonates do not show the expected chemistry of malonic esters; the electrophile reacts preferentially at the sulfur atom, α, β-Unsaturated dithio and thiono esters have been prepared by Wittig-Horner reactions, by Peterson synthesis, and by aldol condensations. α, β-Acetylenic dithio and thiono esters were obtained for the first time. In the formation of thiopeptide bonds from α-amino dithio esters the racemization observed seems to be of fundamental importance. Dianions of dithio acids were found to condense with different electrophiles.