Carbon-Phosphorus Coupling from C^N Cyclometalated Au(III) Complexes.

With the aim of exploiting new organometallic species for cross-coupling reactions, we report here on the Au-III-mediated C-aryl-P bond formation occurring upon reaction of C<^>N cyclometalated Au-III complexes with phosphines. The [Au(C<^>N)Cl-2] complex 1 featuring the bidentate 2-benzoylpyridine ((CN)-N-CO) scaffold was found to react with PTA (1,3,5-triaza-7-phosphaadamantane) under mild conditions, including in water, to afford the corresponding phosphonium 5 through C-P reductive elimination. A mechanism is proposed for the title reaction based on in situ P-31{H-1} NMR and HR-ESI-MS analyses combined with DFT calculations. The C-P coupling has been generalized to other C<^>N cyclometalated Au-III complexes and other tertiary phosphines. Overall, this work provides new insights into the reactivity of cyclometalated Au-III compounds and establishes initial structure-activity relationships to develop Au-III-mediated C-P cross-coupling reactions.