THE REACTION BETWEEN THIOPHOSGENE AND TRIALKYL PHOSPHITES

Abstract
The reaction between trialkyl phosphites and thiophosgene, even at low temperature, does not lead to esters of thiocarbonyl bisphosphonic acid as had previously been reported. The initial products appear to be stabilised phosphorus ylids formed by two carbophilic and one thiophilic reactions between thiophosgene and the trialkyl phosphite with no desulfuration. Following thermal or acidic treatment, the ylids undergo protonation-dealkylation reactions to give phosphorothio-substituted methane bisphosphonates.