Studies of reactions of dimethylphosphoramidic difluoride with trans-2-(N,N-dialkylamino)cycloalkanols in the presence of various sulfur-containing nucleophiles

Article abstract of DOI:10.1007/BF02495700

The reactions of dimethylphosphoramidic difluoride (1) with trans-2-(N,N-dialkylamino)cycloalkanols were studied in the presence of various sulfur-containing nucleophiles and Et₃N. When O,O-diisopropyl thiophosphoric acid was used as a nucleophile, the corresponding O,O-diisopropyl S-[2-(N,N-dialkylamino)cycloalkyl] thiophosphates were obtained in satisfactory yields. The direction of this reaction in the presence of O-isopropyl toluenephosphonothioic acid depends on the pK₃ of aminoalcohol, namely, the amount of O-isopropyl tolylphosphonofluoridate that was formed along with O-isopropyl S-[2-(N,N-dialkylamino)cycloalkyl] tolylphosphonothioates was increased as the pK₃ increased. The reactions of compound 1 with trans-2-(N,N-dialkylamino)cycloalkanols and thioacetic acid afforded 2-(N,N-dialkylamino)cycloalkanethiols, certain of which were readily oxidized to the corresponding disulfides. In the case of potassium ethyl xanthate, the composition of the reaction products depends on the nature of aminoalcohol. X-ray diffraction analysis of S-(2-piperidinocyclohexyl) N,N-dimethyldithiocarbamate demonstrated that this compound exists as the trans isomer. This fact supports the reaction mechanism, which we have suggested previously and which involves the formation of aziridinium cations followed by their opening under the action of nucleophilic agents.