Base-Triggered Oxidative Addition to Gold.

The coordination of secondary phosphine oxides (SPO) was shown to efficiently promote the activation of C(sp ² )-I bonds by gold, as long as a base is added (NEt ₃ , K ₂ CO ₃ ). These transformations stand as a new type of chelation-assisted oxidative addition to gold. The role of the base and the influence of the electronic properties of the P-ligand were analyzed computationally. Accordingly, the oxidative addition was found to be dominated by Au→(Ar-I) backdonation. In this case, gold behaves similarly to palladium, suggesting that the inverse electron flow reported previously (with prevailing (Ar-I)→Au donation, resulting in faster reactions of electron-enriched substrates) is a specific feature of electron-deficient cationic gold(I) complexes. The reaction gives straightforward access to (P=O,C)-cyclometallated Au(III) complexes. The possibility to chemically derivatize the SPO moiety at Au(III) was substantiated by protonation and silylation reactions.
(© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)