Deprotonation Attempts on Imidazolium Salt Tethered by Substituted Phenol and Construction of Its Magnesium Complex by Transmetalation

Abstract

Several attempts to deprotonate the imidizolium salt 1-methyl-3-(4,6-di-tert-butyl-2-hydroxybenzyl)imidazolium bromide, H2[CO]Br (4), tethered by substituted phenol to yield anonic carbene species M[CO] (M = Li, Na) resulted in the formation of {Na[ON](THF)}2 (5) and {Li[ON](THF)}2 (6) (1-methyl-2-(4,6-di-tert-butyl-2-hydroxybenzyl)imidazole, H[ON]) after warming to room temperature from −78 °C due to 1,2-aryloxy migration. Treatment of in-situ-generated M[CO] with 1.0 equiv of MesMgBr (Mes = 2,4,6-Me3C6H2) produced a rare magnesium NHC complex, {Mg[OC](Mes)}2 (8). Both 5 and 8 have been characterized by an X-ray diffraction study