The isomerization 7 -.8 is thought to occur as shown in
Scheme 11. The hexacoordinate phosphorus intermediate is
analogous to a compound actually made from pyridine and a
The experiments herein described support the interpretation
given for the role of amines in phosphorylation reactions in
aprotic solvent^.^ Moreover, the observed silyl-transfer from
aryl-oxygen to phosphorane-oxygen, 7 -c 8, could reflect a
significant and more general mechanism in silicon chemistry.I5
The driving force for this isomerization may be provided by
a higher stability of the bond (R0)4P-O-SiR'3 vs. AR-O-
SIR;. This may be true also for (R0)2P(O)-O-SiR'3, and this
point is being investigated further.
References and Notes
(1)For reviews of the extensive literature see (a)F. Ramirez, Acc. Chem.Res.,
1, 168 (1968):(b) F. Ramirez. Synthesis, 2,90 (1974);(c) D.Hellwinkel
in "Organic phosphorus Compounds", Vol. 3,G. M. Kosoiapoff and L. Maier,
Ed., Wiley-lnterscience, New York, N.Y., 1972,Chapter 58.p 185;(d)E.
A. Arbuzov and N. A. Polezhaeva, Usp.Khim., 43,933(1974).