Continuous Flow Synthesis of Metal-NHC Complexes*

Abstract

The use of weak bases and mild conditions is currently the most sustainable and attractive synthetic approach for the preparation of late-transition metal complexes, some of which are widely used in catalysis, medicinal chemistry and materials science. Herein, the use of cuprate, aurate or palladate species for a continuous flow preparation of Cu^I , Au^I and Pd^II -NHC complexes is reported. All reactions examined proceed under extremely mild conditions and make use of technical grade acetone as solvent. The scalability of the process was exemplified in a multigram-scale synthesis of [Cu(IPr)Cl].

Keywords: N-heterocyclic carbene ligands; flow continuous synthesis; green solvents; metal complexes; weak-base route.