Continuous centrifugation and filtration for assessing the catalytic significance of metal nanoparticles forming in situ during the palladium-catalyzed arylation of N-methylindole

Abstract

We demonstrate that continuous centrifugation of the reaction mixture can alter the trajectory of a palladium catalyzed C–H functionalization reaction in which nanoparticles are forming in situ from molecular precatalysts. By the action of the centrifuge the nanoparticles are sequestered in an immiscible layer as they form, preventing them from interacting with the substrate or forming equilibria with molecular catalyst species. The use of continuous centrifugation to assess the catalytic relevance of nanoparticles that are forming in situ is compared to a more conventional filtration strategy.