Nitrogen → 4,4-difluoro-2-[5-(4-trimethylsilanylethynyl-phenyl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 2-[5-(4-bromo-phenyl)-1H-imidazol-2-yl]-4,4-difluoro-pyrrolidine-1-carboxylic acid tert-butyl ester (700 mg, 1.56 mmol), TMS-acetylene (1.11 mL, 7.79 mmol) and triethylamine (1.1 mL, 7.8 mmol) in DMF (8 mL) was degassed with N2 gas for 20 minutes. To the degassed solution was added Pd(PPh3)4 (180 mg, 0.16 mmol) and CuI (14.8 mg, 0.078 mmol). The pressure flask was sealed then heated at 80° C. overnight. After cooling to room temperature, the reaction was concentrated then diluted with EtOAc and washed with water. The aqueous phase was back-extracted two times then the organic phases were combined and dried over Na2SO4. After concentration, the crude material was purified by silica gel chromatography (10-50% EtOAc-hexanes gradient) to afford 4,4-difluoro-2-[5-(4-trimethylsilanylethynyl-phenyl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester (547 g, 1.23 mmol, 79% yield). LCMS-ESI+: calc'd for C23H30F2N3O2Si: 446.2 (M+H+). Found: 445.8 (M+H+).

Provenance & Evidence