An Approach to P=N Bond Formation: Straightforward Synthesis of Arylurea‐Derived Phosphazenes via Condensation of Ph 3 P=O with N ‐Monosubstituted Arylureas

The Hendrickson's reagent‐mediated formation of the P=N bond provides access to arylurea‐derived phosphazenes compounds using readily available N ‐monosubstituted arylureas and Ph 3 P=O. Various functional groups were tolerated to give arylurea‐derived phosphazenes in the yield of 71–93%. The reaction also provides an alternative strategy for constructing compounds containing P=N bond. In this transformation, the Hendrickson's reagent unprecedented selectively reacts with the free amine group instead of the oxygen atom of N ‐monosubstituted arylurea. In addition, we found that thioureas could act as an effective thionating agent by converting Ph 3 P=O to Ph 3 P=S.