A robust methodology for the synthesis of phosphorothioates, phosphinothioates and phosphonothioates.

A robust methodology for the synthesis of phosphorothioates, phosphinothioates and phosphonothioates, including those bearing low molecular weight S-alkyl side-chains, is presented. Application of the “caesium effect” in conjunction with the disulfide 3,3’-dithiobis(propionitrile), which acts as a shelf-stable sulfur source, avoids recourse to malodorous alkanethiols and toxic P−Cl precursors. A diverse range of sulfur-containing organophosphorus targets, including phosphorus-based heterocycles, may be prepared in consistently high yields. This chemistry also provides ready access to the corresponding DBU salts which are potential substrates for Pd-catalysed coupling reactions. (Figure presented.).