Carbon–Phosphorus Coupling from C^N Cyclometalated AuIII Complexes

Abstract

With the aim of exploiting new organometallic species for cross-coupling reactions, we report here on the AuIII-mediated Caryl−P bond formation occurring upon reaction of C^N cyclometalated AuIII complexes with phosphines. The [Au(C^N)Cl2] complex 1 featuring the bidentate 2-benzoylpyridine (CCON) 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 31P{1H} NMR and HR-ESI-MS analyses combined with DFT calculations. The C−P coupling has been generalized to other C^N cyclometalated AuIII complexes and other tertiary phosphines. Overall, this work provides new insights into the reactivity of cyclometalated AuIII compounds and establishes initial structure–activity relationships to develop AuIII-mediated C−P cross-coupling reactions.