Heterogenization of Pd-NHC complexes onto a silica support and their application in Suzuki-Miyaura coupling under batch and continuous flow conditions

The heterogenisation of a new family of Pd-NHC complexes is reported via a straightforward and efficient synthetic procedure. These silica-immobilised materials were successfully applied as catalysts in the Suzuki-Miyaura coupling of aryl chlorides and bromides under mild conditions. The materials exhibited improved stability when the catalytic reaction was run under anhydrous conditions and could be recycled up to five times without significant loss of activity. When the reaction was run within a continuous flow microreactor, these catalysts showed good activity after at least two hours on stream.