A solution of (1R,3S,4S)-tert-butyl 3-(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzo[d]imidazol-2-yl)-2-azabicyclo[2.2.1]heptane-2-carboxylate (1.0 g, 2.3 mmol), methanol (10 mL), and 4M HCl in dioxane (11 mL, 44 mmol) was stirred at room temperature. The reaction was thoroughly concentrated after one hour. The resulting residue was dissolved in dimethylformamide (11.4 mL). To this solution was added (S)-2-(methoxycarbonylamino)-3-methylbutanoic acid (419 mg, 2.4 mmol) and HATU (909 mg, 2.4 mmol). Diisopropylethylamine (1.4 mL, 8.1 mmol) was added and the reaction was stirred at room temperature. After thirty minutes, the reaction was diluted with ethyl acetate. The organic phase was washed with water and brine, dried (Na2SO4) and concentrated. The crude material was purified by flash column chromatography to yield methyl (S)-3-methyl-1-oxo-1-((1R,3S,4S)-3-(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzo[d]imidazol-2-yl)-2-azabicyclo[2.2.1]heptan-2-yl)butan-2-ylcarbamate (1.08 g, 95%).
