1-Hydroxybenzotriazole → (2s)-2-((1r,2s)-2-{[2-(3-Hydroxy-phenyl)-ethyl]-methyl-carbamoyl}-1-methylsulfanyl-propyl)-pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a stirred solution of (2S)-2-[(1R,2S)-2-carboxy-1-methylsulfanyl-propyl]-pyrrolidine-1-carboxylic acid tert-butyl ester (1.70 g, 5.6 mmol) in CH2Cl2 (20 mL) were added N-methyl-3-hydroxyphenethylamine hydrobromide (2.44 g, 11.2 mmol), BOP (3.72 g, 8.4 mmol), HOBT (1.29 g, 8.4 mmol), and diisopropylethylamine (4.88 mL, 28.0 mmol) at room temperature. After being stirred at room temperature for 2 hr, the mixture was quenched with 1N HCl (80 mL×3), extracted with AcOEt, dried (MgSO4) and concentrated in vacuo to give a crude oil (3.83 g), which was then purified by flash column chromatography (hexane:AcOEt=1:1) to give (2S)-2-((1R,2S)-2-{[2-(3-hydroxy-phenyl)-ethyl]-methyl-carbamoyl}-1-methylsulfanyl-propyl)-pyrrolidine-1-carboxylic acid tert-butyl ester as a gum (1.38 g, 56%).

Provenance & Evidence