Synthesis and Reactivity of Heteroleptic Ga-P-C Allyl Cation Analogues.

ABSTRACT

Oxidative addition of cyclic alkyl(amino)carbene-coordinated phosphinidenes (Me cAAC)PX to LGa affords gallium-coordinated phosphinidenes LGa(X)-P(Me cAAC) (L=HC[C(Me)N(2,6-i-Pr2 C6 H3 )]2 ; X=Cl 1, Br 2), which react with NaBArF 4 and LiAl(ORF )4 to [LGaP(Me cAAC)][An] (An=B(C6 H3 (CF3 )2 )4 3, B(C6 F5 )4 4, Al(OC(CF3 )3 )4 5). The cations in 3-5 show substantial Ga-P double bond character and represent heteronuclear analogues of allyl cations according to quantum chemical calculations. The reaction of 4 with 4-dimethylaminopyridine (dmap) to adduct 6 confirms the strong electrophilic nature of the gallium center, whereas 5 reacts with ethyl isocyanate with C-C bond formation to the γ-C atom of the ß-diketiminate ligand and formation of compound 7.