A more sustainable and efficient access to IMes•HCl and IPr•HCl by ball-milling

Herein is described a mechanochemical one-pot two-step procedure giving access to various NHC (N-heterocyclic carbene) precursors. This original approach enabled the production of the widely used IPr center dot HCl, IMes center dot HCl, Io-Tol center dot HCl and ICy center dot HCl in much better yields than conventional solvent-based procedures, while the environmental impact was drastically reduced.