To solution of 3-chloro-4-(2-(5-(2-(4-chloro-3-methoxyphenyl)propan-2-yl)-1-(4-fluorophenyl)-1H-imidazol-2-yl)ethyl)-5-fluorobenzoic acid (540 mg) in a mixture of toluene (5 mL) and tert-butanol (1.5 mL) cooled to 0° C. was added diphenyl phosphoryl azide (DPPA) (1.1 eq, 302 mg) followed by DIPEA (1.3 eq, 226 μL). During addition of base, the white slurry became a clear solution, which was heated at 80° C. After 16 h, complete conversion was observed by LC-MS. The reaction was diluted with EtOAc, washed with satd NaHCO3, dried (Na2SO4), concentrated and purified by chromatography (silica, EtOAc/Hex, 10-60%) to yield tert-butyl 3-chloro-4-(2-(5-(2-(4-chloro-3-methoxyphenyl)propan-2-yl)-1-(4-fluorophenyl)-1H-imidazol-2-yl)ethyl)-5-fluorophenylcarbamate (230 mg). MS (EI) m/z 616 (MH+).
