Intramolecular Arene C–H to C–P Functionalization Mediated by Nickel(II) and Palladium(II)

A tris­(phosphine)
ligand with a triarylbenzene backbone was employed to support mono-nickel­(II)
and
-palladium­(II) complexes. Two phosphine arms coordinated to the metal
center, while the third phosphine was found to form a C–P bond
with dearomatization of the central arene. Deprotonation effected
the rearomatization of the central ring and metal reduction from M­(II)
to M(0). The overall conversion corresponds to a functionalization
of an unactivated arene C–H bond to a C–P bond. This
transformation represents a rare type of mechanism of C–H functionalization,
facilitated by the interactions of the group 10 metal with the arene
π system. This conversion is reminiscent of and expands the
scope of recently reported intramolecular rearrangements of biaryl
phosphine ligands common in group 10 catalysis.