Influence of 18-Crown-6 Ether Coordination on the Catalytic Activity of Potassium and Calcium Diarylphosphinites in Hydrophosphorylation Reactions

The addition of 18-crown-6 ether (1,4,7,10,13,16-hexaoxacyclooctadecane) to tetranuclear [(thf)K(OPAryl(2))](4) and [(thf(4)Ca(OPAryl(2))(2)] yields the corresponding mononuclear complexes [(18C6)K(OPAryl(2))] [Aryl = Ph (1a), Mes (1b)] and [(18C6)Ca(OPAryl(2))(2)], [Aryl = Ph (2a), Mes (2b)]. The metathesis reaction of [(thf)K(C)PAryl(2))](4) with caI(2) yields the calciate [K2Ca(thf)(x) {OPMes(2)}(4)]. The addition of dimesitylphosphane oxide and crystallization from a hexane solution gives [K2Ca{OPMes}(4){Mes(2)P(O)H}] (3). The complexes [(thf)K(OPMes(2))](4,) [(thf)(4)Ca(OPMes(2))(2)], 1b, 2b, and the calciate 3 are tested as catalysts in the hydrophosphorylation of isopropylisocyanate with dimesitylphosphane oxide, quantitatively yielding N-isopropyl(dimesitylphosphoryl)formamide. The potassium, complexes calcium, congeners, and coordination of 18-crown-6 decelerates the catalytic conversion. are more efficient catalysts than the