Heterogeneously Pd/C catalysed procedure for the vinylation of aryl bromides

Heterogeneous Pd/C catalyst was applied to the Suzuki–Miyaura vinylation of various aryl and heteroaryl halides under aerobic and mild reaction conditions [1.0 mmol aryl halide, 1.5 mmol potassium vinyltrifluoroborate, 3.0 mmol K3PO4·H2O, 0.1 mol% Pd/C(EVO), 1 mL NMP, 100 °C, 24 h]. Useful isolated yields (57–73%) were achieved. In some cases, the catalytic system should be tuned to face the reactivity of the aryl halides: while 0.1 mol% Pd/C is sufficient for almost all aryl bromides, 1.0 mol% Pd/C was used for free phenols.The heterogeneous catalyst was proved to be stable upon several catalytic cycles; however, the results showed that this was dependent on addition of the base. Hot-filtration experiment indicates that the activity was mainly due to leached Pd-species, indicating that the Pd/C catalyst acts as a palladium reservoir.

Graphical abstractHeterogeneous Pd/C catalyst was applied to the vinylation of various aryl and heteroaryl halides giving useful isolated yields under aerobic and mild reaction conditions. The catalyst was proved to be stable upon several catalytic cycles given that base was added in the reaction mixture. Hot-filtration experiment indicates that the activity was mainly due to leached Pd-species.Figure optionsDownload full-size imageDownload as PowerPoint slide