Exploring the Chemoselectivity towards Cysteine Arylation by Cyclometallated AuIIICompounds: New Mechanistic Insights

To gain more insight into the factors controlling efficient cysteine arylation by cyclometallated Au(III)complexes, the reaction between selected gold compounds and different peptides was investigated by high-resolution liquid chromatography electrospray ionization mass spectrometry (HR-LC-ESI-MS). The deduced mechanisms of C-S cross-coupling, also supported by density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) calculations, evidenced the key role of secondary peptidic gold binding sites in favouring the process of reductive elimination.