Triethylamine → (3R,4S)-3-[(S)-3-(4-fluorobenzyl)-piperidine-1-carbonyl]-4-[(R)-1-phenyl-ethylamino]-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

A cloudy solution of (3R,4S)-4-[(R)-1-phenyl-ethylamino]-pyrrolidine-1,3-dicarboxylic acid 1-tert-butyl ester (80 mg, 240 μmol) in methylene chloride (5 mL) was treated with benzotriazol-1-yloxy-tripyrrolidinophosphonium hexafluorophosphate (151 mg, 290 μmol) and triethylamine (77 μL, 550 μmol) and stirred for 5 minutes. A solution of the (S)-3-(4-flourobenzyl)-piperdine prepared above in methylene chloride (5 mL) was added and the mixture was stirred at room temperature. After 18 h, the mixture was washed with water and saturated NaHCO3, dried (Na2SO4) and concentrated. The residue was purified by flash column chromatography (50% ethyl acetate/hexanes) to provide the product as a gum (100 mg, 82%).

Provenance & Evidence