5062
J. Am. Chem. SOC.1991, i13, 5062-5063
New Synthesis and First X-ray Crystal Study of a C-Borylated Phosphorus Ylide Klaus Horchler von Locquenghien,+** Antoine Baceiredo,' Roland Boese,*J and Guy Bertrand*+ Laboratoire de Chimie de Coordination du CNRS 205, route de Narbonne, 31 077 Toulouse CZdex, France Institut f u r Anorganische Chemie, Universitiit-GH Essen Universitatsstrasse 3-5, 4300 Essen, FRG Received January 29, I991 1131
Phosphorus ylides A have been widely used in organic and organometallic synthesis.I More recently, the synthetic potential of boron methylidenide ions B has been demonstrated.2 Theoreticians have been attracted by the unusual pho~phorus-carbon~ and boron-carbon bonding4 in such compounds. Numerous socalled stabilized phosphorus ylides have been studied in which the negative charge is delocalized into an o r g a n i ~organometallic,6 ,~ or heteroatomic' framework. Only little attention has been devoted to C-borylated phosphorus ylides C8 although they are of special interest: they can also be considered as C-phosphonio-substituted borataalkenes D. JP=C< A
>li=C< B
+P.C< C
7-
4-+
d-C
