Synthesis of precursor imidazolium salts for the synthesis of N-heterocyclic carbines used as ligands for the enantioselective preparation of heterosteroids compounds

Abstract

The imidazolium salts 1-phenyl-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)-1H-imidazol-3-ium bromide (4), and 1-(pyrimidin-2-yl)-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan- 2-yl)propyl)-1H-imidazol-3-ium bromide (5) were respectively prepared by coupling reaction of the precursors 1-phenyl-1H-imidazole (1) and 2-(1H-imidazol-1-yl)pyrimidine (2) with 2-(3- Bromopropyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(3). The purity of these compounds was confirmed by spectroscopic data. The NMR spectra showed all the signals and the structures were confirmed by HRMS.