Iron-catalysed substrate-directed Suzuki biaryl cross-coupling

Although the replacement of ubiquitous palladium catalysts with more sustainable iron-based analogues continues apace, the simple biaryl Suzuki cross-coupling reaction remains stubbornly elusive. It appears that the main issue hampering the reaction is activation of the aryl halide C-X bond. Here we show that a simple N-pyrrole amide and related directing groups on the aryl halide substrates facilitate this process by transient pi-coordination to the iron centre. This allows iron-catalysed Suzuki biaryl cross-coupling to proceed, under mild conditions, with alkyllithium-activated aryl pinacol boronic esters.