Secondary Benzylation with Benzyl Alcohols Catalyzed by A High-Valent Heterobimetallic Ir−Sn Complex

A highly efficient secondary benzylation procedure has been
demonstrated using a high-valent heterobimetallic complex
[Ir2(COD)2(SnCl3)2(Cl)2(μ-Cl)2] 1 as the catalyst in 1,2-dichloroethane to afford the corresponding benzylated products in moderate to excellent yields. The reaction was
performed not only with carbon nucleophiles (arenes and
heteroarenes) but also with oxygen (alcohol), nitrogen (amide
and sulfonamide), and sulfur (thiol) nucleophiles. Mechanistic investigation showed the intermediacy of the ether in
this reaction. An electrophilic mechanism is proposed from
Hammett correlation.