Hemithioacetal

In organic chemistry, hemithioacetals (or thiohemiacetals) are organosulfur compounds with the general formula R−CH(−OH)−SR’. They are the sulfur analogues of the acetals, R−CH(−OH)−OR’, with an oxygen atom replaced by sulfur (as implied by the thio- prefix). Because they consist of four differing substituents on a single carbon, hemithioacetals are chiral. A related family of compounds are the dithiohemiacetals, with the formula R−CH(−SH)−SR’.^[1] Although they can be important intermediates, hemithioacetals are usually not isolated, since they exist in equilibrium with thiols (−SH) and aldehydes (−CH=O).