Citric Acid → (S)-2-[3-tert-Butylsulfanyl-2-(2-carboxy-2-methyl-propyl)-1-(4-chloro-benzyl)-1H-indol-5-yloxymethyl]-pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

The ester from Step 4 (0.16 g, 0.26 mmol) was dissolved in MeOH (1 mL), THF (1 mL), and water (1 mL). Lithium hydroxide (0.6 g, 1.43 mmol) was added, and the reaction was heated for 12 hours until no starting material was seen by TLC analysis. The reaction was diluted with water, acidified to pH 5 with citric acid, and extracted with EtOAc. The combined organic layers were washed with water, dried over MgSO4, filtered, and concentrated. The residue was purified on silica gel (0 to 40% EtOAc in hexanes) to give the desired product (C-5; X═Cl).

Provenance & Evidence