Synthesis of 1-diethoxyphosphoryl-1-methylthio-thioacetamides and 1-methylthioethenethioamides. An unusual intramolecular α-desulfenylation of thioacetamides

Article abstract of DOI:10.1016/S0040-4020(01)80207-6

Addition of the lithiated α-phosphoryl sulfide 1-Li to alkyl or aryl isothiocyanates 4(a-f) and phenyl isocyanate 4g was found to afford 1-diethoxyphosphoryl-1methylthio-thioacetamides 5(a-f) and - acetamide 5g, respectively. In the case of the reaction with the p-chlorophenyl isothiocyanate 4e, the α-desulfenylated product 6 was isolated and on the basis of ³¹P-NMR experiments a mechanism of its formation was proposed. The phosphonates 5(a-f), which exist in the thione form, were found to undergo the Horner-Wittig reaction with aromatic aldehydes affording 1-methylthioethenethioamides 14(a-f).