Hydrochloric Acid → di-tert-butyl (2S,2'S)-2,2'-{[(1S,4S)-1,4-dihydroxybutane-1,4-diyl]bis (6-fluoro-1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-benzimidazole-5,2-diyl)}dipyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of (R)-(+)-α,α-diphenyl-2-pyrrolidinemethanol (59.9 mg, 0.24 mmol) in THF (2.8 mL) was added trimethylborate (0.034 mL, 0.31 mmol), and the resultant solution was stirred for 90 minutes. The solution was cooled to 0° C. and N,N-diethylaniline borane (0.4 mL, 2.2 mmol) was added in portions over 30 minutes with stirring continued at 0° C. This solution was added via cannula to a 0° C. solution of di-tert-butyl (2S,2′S)-2,2′-[(1,4-dioxobutane-1,4-diyl)bis(6-fluoro-1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-benzimidazole-5,2-diyl)]dipyrrolidine-1-carboxylate (265 mg, 0.28 mmol) in THF (2.8 mL) and then warmed to room temperature and stirred for 16 hours. The solution was cooled to 0° C. and CH3OH (0.09 mL, 2.2 mmol) was added, and the solution was warmed to room temperature and stirred for 2 hours. 1N HCl was added, and the aqueous solution was extracted with EtOAc. The combined extracts were washed with brine, dried (Na2SO4), filtered and concentrated. Purification was run by flash chromatography (0-3% CH3OH/CH2Cl2) to give the title compound (248 mg, 0.26 mmol, 93%).

Provenance & Evidence