Reaction SMILES: C(OC(N1CC(COC(F)F)CC1C1NC(C2C=CC(Br)=CC=2)=CN=1)=O)(C)(C)C.[C:30]([O:34][C:35]([N:37]1[CH2:41][CH:40]([CH2:42][O:43][CH:44]([F:46])[F:45])[CH2:39][CH:38]1[C:47]([O:49][CH2:50]C(C1C=CC(Br)=CC=1)=O)=[O:48])=[O:36])([CH3:33])([CH3:32])[CH3:31]>C1(C)C=CC=CC=1.CCOC(C)=O>[CH3:50][O:49][C:47]([CH:38]1[CH2:39][CH:40]([CH2:42][O:43][CH:44]([F:46])[F:45])[CH2:41][N:37]1[C:35]([O:34][C:30]([CH3:33])([CH3:32])[CH3:31])=[O:36])=[O:48]
Reactant: CC(C)(C)OC(=O)N1CC(COC(F)F)CC1C(=O)OCC(=O)c1ccc(Br)cc1
Agent: CC(C)(C)OC(=O)N1CC(COC(F)F)CC1c1ncc(-c2ccc(Br)cc2)[nH]1
Solvent: CCOC(C)=O
Solvent: Cc1ccccc1
Product: COC(=O)C1CC(COC(F)F)CN1C(=O)OC(C)(C)C
Temperature: 25 °C
Yield: 68.3 %

Procedure:
4-Hydroxymethyl-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (584 mg, 2.25 mmol) and CuI (86 mg, 0.45 mmol) were suspended in MeCN (10 mL). The reaction mixture was heated to 45° C. and difluoro-fluorosulfonyl-acetic acid (0.465 mL, 4.5 mmol) was added dropwise over the course of 30 min. Stirring was continued for another 3 h, after which the reaction mixture was cooled to RT and concentrated. The residue was taken up in EtOAc and washed with saturated aqueous NaHCO3 and brine then dried over MgSO4, filtered and concentrated. The crude residue was purified by silica column chromatography (19% to 40% EtOAc/Hex) to afford the title compound (394 mg, 57%). 4-Difluoromethoxymethyl-pyrrolidine-1,2-dicarboxylic acid 2-[2-(4-bromo-phenyl)-2-oxo-ethyl]ester 1-tert-butyl ester: 4-Difluoromethoxymethyl-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (398 mg, 1.29 mmol) was dissolved in MeOH (8 mL) and LiOH (1 M in H2O, 2 mL, 2 mmol) was added. After stirring at RT for 5 h, the MeOH was removed under reduced pressure. The aqueous solution was poured into a separatory funnel, diluted with 1 M HCl (2 mL, 2 mmol) and extracted with DCM (3×). The combined organics were dried over MgSO4, filtered and concentrated. The residue was dissolved in MeCN (4 mL) and treated with 2,4′-dibromoacetophenone (200 mg, 0.719 mmol), and triethylamine (0.100 mL, 0.719 mmol). After stirring for 15 h, the solvent was removed. The crude residue was purified by silica column chromatography (10% to 35% EtOAc/Hex) to afford the title compound (303 mg, 94%). 2-[5-(4-Bromo-phenyl)-1H-imidazol-2-yl]-4-difluoromethoxymethyl-pyrrolidine-1-carboxylic acid tert-butyl ester: 4-Difluoromethoxymethyl-pyrrolidine-1,2-dicarboxylic acid 2-[2-(4-bromo-phenyl)-2-oxo-ethyl]ester 1-tert-butyl ester (303 mg, 0.615 mmol) was dissolved in PhMe (12 mL) and treated with NH4OAc (948 mg, 12.3 mmol). The stirred mixture was refluxed for 23 h then cooled to RT and diluted with EtOAc. The organic phase was washed with saturated aqueous NaHCO3 and brine then dried over MgSO4, filtered and concentrated. The crude residue was purified by silica column chromatography (25% to 50% EtOAc/Hex) to afford the title compound (130 mg, 45%). (1-{2-[5-(4-Bromo-phenyl)-1H-imidazol-2-yl]-4-difluoromethoxymethyl-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester: 245-(4-Bromo-phenyl)-1H-imidazol-2-yl]-4-difluoromethoxymethyl-pyrrolidine-1-carboxylic acid tert-butyl ester was dissolved in DCM (4 mL) and treated with HCl (4.0M in dioxane, 1 mL, 4 mmol). After 2.5 h, the solution was concentrated and the residue was treated with 2-Methoxycarbonylamino-3-methyl-butyric acid (55 mg, 0.315 mmol) and HATU (120 mg, 0.315 mmol). The solids were suspended in DMF (3 mL) and the reaction mixture was cooled to 0° C. before triethylamine (0.25 mL, 1.43 mmol) was added in a dropwise fashion. After 30 min, the mixture was warmed to RT. After another 1 h, it was diluted with EtOAc and washed with saturated aqueous NaHCO3 and brine. Then it was dried over MgSO4, filtered and concentrated. The crude residue was purified by silica column chromatography (60% to 100% EtOAc/Hex) to afford the title compound (92 mg, 61%). (1-O-Difluoromethoxymethyl-2-[5-(4′-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-biphenyl-4-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester: (1-{2-[5-(4-Bromo-phenyl)-1H-imidazol-2-yl]-4-difluoromethoxymethyl-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (42 mg, 0.174 mmol), [2-Methyl-1-(2-{5-[4-(4,4,5,5-tetramethyl-[1,3 ,2]dioxaborolan-2-yl)-phenyl]-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl)-propyl]-carbamic acid methyl ester (95 mg, 0.191 mmol), Pd(PPh3)4 (20 mg, 0.0174 mmol) and K2CO3 (2M in H2O, 0.191 mL, 0.383 mmol) were combined in 1,2-dimethoxyethane (2 mL). The mixture was degassed with bubbling N2 for 12 min then heated to 85° C. for 4 h. After cooling to RT, the reaction mixture was diluted with EtOAc then washed with water and brine. The organic layer was dried over MgSO4, filtered and concentrated. The crude residue was purified by HPLC to provide the title compound (42 mg, 30%). MS (ESI) m/z 819 [M+H]+.