Bulky Monophosphine Ligand Synthesis by Nucleophilic Addition to Peri ‐Functionalized Phosphine Isoindolium Salts

In this article, we demonstrate the synthesis of 3‐substituted isoindoline monophosphine ligands by nucleophilic addition of Grignard reagents to peri ‐functionalized phosphine isoindolium salts. The bulky, α ‐branched isoindoline ligands were metalated using (dimethylsulfide)gold(I)chloride to obtain the phosphine gold(I)chloride complexes with a ligand conformation which is comparable to Buchwald biarylphosphine ligands induced by steric strain. In gold‐catalyzed reactions, the gold complexes show high catalytic activity at low catalyst loadings, outcompeting the established catalytic systems (Ph ₃ P)AuCl and (XPhos)AuCl.