Reaction of oxophosphorane-sulphenyl and -selenenyl chlorides with dialkyl trimethylsilyl phosphites. Novel synthesis of compounds containing a sulphur or selenium bridge between two phosphoryl centres

Abstract

A novel highly efficient synthesis of sym-tetra-alkyl monothio- and monoseleno-pyrophosphates (RO)₂P(O)XP(O)(OR′)₂(X = S,Se) based on the condensation of dialkoxyoxophosphorane-sulphenyl or -selenenyl chlorides (RO)₂P(O)XCl (X = S,Se) with dialkyl trimethylsilyl phosphites (RO)₂POSiMe₃(9) is described. Remarkably selective reaction of a O,O′-dialkyl O″-trimethylsilyl selenophosphate (RO)₂P(Se)OSiMe₃(13) with sulphuryl dichloride in the presence of an equimolar amount of a phosphite (9) leads to the formation of sym-monoselenopyrophosphates in excellent yield. A new rearrangement in phosphorus chemistry, sym-monoselenopyraphosphates (11) to asym-monoselenopyrophosphates (12), has been observed.