(RhAr)-Ar-I/(AuAr)-Ar-I ' Transmetalation: A Case of Group Exchange Pivoting on the Formation of M-M ' Bonds through Oxidative Insertion

摘要

By combining kinetic experiments, theoretical calculations, and microkinetic modeling, we show that Pf/Rf (C6F5/C6Cl2F3) exchange between [AuPf(AsPh3)] and trans-[RhRf(CO)(AsPh3)(2)] does not occur by typical concerted Pf/Rf transmetalation via electron-deficient double bridges. Instead, it involves asymmetric oxidative insertion of the Rh-I complex into the (Ph3As)Au-Pf bond to produce a [(Ph3As)Au-RhPfRf(CO)(AsPh3)(2)] intermediate, followed by isomerization and reductive elimination of [AuRf(AsPh3)]. Interesting differences were found between the LAu-Ar asymmetric oxidative insertion and the classical oxidative addition process of H-2 to Vaska complexes.