Synthesis of Dialkyl Phosphoroselenocyanatidates and Their Rearrangement to Dialkyl Phosphoroiso-selenocyanatidates

The synthesis of diaryl and dialkyl phosphoroisoseleno-cyanatidates (I) has been described only recently^1,2. However, their isomers, dialkyl or diaryl phosphoro-selenocyanatidates (II) are, to our knowledge, unknown. In our attempts of their synthesis we found that the preparation of II in the way analogous to the synthesis of the corresponding thiocyanatidates ³was not possible due to the inaccessibility of the 0,0-dineopentoxy-oxo-phosphoraneselenenyl chloride (III). Reaction of triethylamminium 0,0-dineopentyl-phosphoroselenoate (IVa) with sulphuryl chloride at -70[ddot]C in CH₂Cl₂ solution led