SYNTHESIS OF TRIS(DIORGANYLPHOSPHINO)PHOSPHINES WITH SUBSTITUENTS OF LOW STERIC HINDRANCE

The reaction of M(I)P(SiMe3)2 (M(I) = Li, Na, K) with diorganylchlorop hosphines forms tris(diorganylphosphino)phosphines P(PR2)3 (R = Cy, Ph , i-Pr, n-Pr, Et, Me). In all cases, the stepwise formation reaction p roceeds via di- and triphosphines resulting in iso-tetraphosphines whi ch are stable in solution. Only the compounds with bulky substituents (R = Cy, Ph) can be isolated. By using quantumchemical procedures it i s possible to get information about the pyramidal structure and the re action behaviour. In agreement with these results orbitally controlled reactions occur where nucleophiles attack the central phosphorus atom .