Phosphonium salts based on 2H-imidazole: synthesis by direct C–H functionalization of imidazole N-oxides

A convenient approach towards previously unknown phosphonium salts containing a non-aromatic 2 H -imidazole moiety is reported. The approach is based on a direct nucleophilic C(sp 2 )-H functionalization of 2 H -imidazole 1-oxides with triphenylphosphine acting as a nucleophile. Herewith, the heterocyclic N -oxide moiety is utilized as an auxiliary group contributing to an abstraction of C-H proton during the elimination process. Newly obtained compounds can be a subject of further modification, e.g. used for the synthesis of monodeuterated 2 H -imidazoles.