The very widely exploited Suzuki biaryl coupling reaction typically requires catalysts based on palladium, but there is an increasing desire to replace this metal with a more sustainable, less expensive alternative, with catalysts based on iron being a particularly attractive target. Here we show that a simple iron-based catalyst with an N-heterocyclic carbene ligand can be used to excellent effect in the Suzuki biaryl coupling of aryl chloride substrates with aryl boronic esters activated by an organolithium reagent. Mechanistic studies suggest the possible involvement of Fe(I) as the lowest oxidation state on the catalytic manifold and show that the challenging step is not activation of the aryl chloride substrate, but rather the transmetallation step. These findings are likely to lead to a renaissance of iron-catalysed carbon–carbon bond-forming transformations with soft nucleophilic coupling partners.

被广泛开发的 Suzuki 联芳基偶联反应通常需要基于钯的催化剂，但人们越来越希望用更可持续、更便宜的替代品来取代这种金属，而基于铁的催化剂是一个特别有吸引力的目标。在这里，我们表明，具有 N-杂环卡宾配体的简单铁基催化剂可用于芳基氯化物与有机锂试剂活化的芳基硼酯的 Suzuki 联芳基偶联，效果极佳。机理研究表明，Fe（I） 可能作为催化歧管上的最低氧化态参与其中，并表明具有挑战性的步骤不是芳基氯化物的活化，而是金属转移步骤。这些发现可能会导致铁催化的碳-碳键形成转化与软亲核偶联伴侣的复兴。