Pyridine → (2S,4R)-2-(2,4,5-trifluoro-benzyloxymethyl)-4-tritylsulfanyl-pyrrolidine-1-carboxylic acid 2-fluoro-phenyl ester

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Reaction Steps

A solution of 0.19 ml (1.58 mmol) trichloromethyl-chloroformate in 20 ml CH2Cl2 was treated at 0° C. with 0.28 ml (3 mmol) 2-fluorophenol and 0.35 ml (3 mmol) quinoline and then stirred for 3 h at room temperature. The reaction was then cooled (0° C.) and a solution of 0.52 g (1 mmol) (2S,4R)-2-(2,4,5-trifluoro-benzyloxymethyl)-4-tritylsulfanyl-pyrrolidine and 0.2 ml (2.5 mmol) pyridine in 3 ml CH2Cl2 was added, followed by 122 mg (1 mmol) DMAP. After 3 h at 0° C. the reaction was evaporated and poured into aqueous 10% KHSO4/Et2O (3×). The organic phases were washed with aqueous 10% NaCl solution, dried over Na2SO4 and evaporated. Flash chromatography on silica gel (hexane/EtOAc 9:1) gave 0.39 g (60%) (2S,4R)-2-(2,4,5-trifluoro-benzyloxymethyl)-4-tritylsulfanyl-pyrrolidine-1-carboxylic acid 2-fluoro-phenyl ester, MS: 658 (MH+).

Provenance & Evidence