One-step preparation of [RuCp*(η6-arene)]+ sandwich complexes

In a single step, several variously functionalized [RuCp* (eta(6)-arene)](+) sandwich complexes have been prepared starting from RuCl3.xH(2)O in yields ranging from 35 to 80%, referring to ruthenium. The protocol covers the preparation of valuable [RuCp*](+)-complexed amino acids. In comparative experiments starting from the oligomer [RuCp* Cl-2](n) and using methanol/methanolate as the reducing agent, the formation of undesired side products was observed, resulting from nucleophilic substitution at the o-chloroanisole complex and from methoxylation of the Cp* ligand. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).