Efficient Suzuki coupling of aryl chlorides catalyzed by tricyclohexylphosphine adducts of cyclopalladated ferrocenylimines

The air and moisture stable tricyclohexylphosphine (PCy3) adducts of dimeric cyclopalladated ferrocenylimines 5 and 6 have been easily synthesized and successfully used in palladium-catalyzed Suzuki cross-coupling of aryl chlorides. Using 0.1 mol% of 6 in the presence of 2 equivalent of Cs2CO3 as base in dioxane at 100 °C provided coupled products in excellent yields in the reaction of non-activated and deactivated aryl chlorides with phenylboronic acid. For activated chlorides such as 4-chloronitrobenzene and 4-chloroacetophenone, the catalyst loadings could be lowered to 0.01 mol% without loss of activity.

Graphical abstractThe air and moisture stable tricyclohexylphosphine (PCy3) adducts of dimeric cyclopalladated ferrocenylimines 5 and 6 have been easily synthesized and characterized by 1H NMR, IR, HRMS and X-ray single crystal analysis. It was found that 5 and 6 were efficient catalysts for the Suzuki coupling of aryl chlorides with phenylboronic acid.Figure optionsDownload full-size imageDownload as PowerPoint slide