A Facile General Synthesis of Thiocarboxylate S-Esters of Glyphosate and Its Derivatives

Various glyphosate thiocarboxylate S-ester derivatives, e. g. S-alkyl 2-(phosphonomethylamino)ethanethioates and S-alkyl 2-[(phenoxyphosphorylmethyl)amino]ethanethioates, are readily synthesized from N-benzyloxycarbonylglycine using N-methylene-tert-butylamine as the methylene transfer reagent followed by nucleophilic phosphorylation with tris(trimethylsilyl) phosphite