Structure and reactivity of late transition metal η³-benzyl complexes.

The coordination of transition metals to organic fragments can yield complexes with fascinating and unexpected binding patterns. The study of metal-benzyl complexes has demonstrated the feasibility of η(3)-coordination, which results in a dearomatized ring. These complexes also offer insight into reaction mechanisms as proposed intermediates in catalytic cycles. In this Review we discuss the synthesis and characterization of these complexes with late transition metals and the subsequent development of catalytic benzylic functionalization methods, including asymmetric variants.