Sodium hydride → (2S,4R)-2-(2,4,5-trifluoro-benzyloxymethyl)-4-tritylsulfanyl-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

A solution of 15.5 g (32.59 mmol) (2S,4R)-2-hydroxymethyl-4-tritylsulfanyl-pyrrolidine-1-carboxylic acid tert-butyl ester and 24.7 g (109.77 mmol) 2,4,5-trifluorobenzylbromide in 700 ml DMF at 0° C. was treated with 2.28 g (52.14 mmol) of 55% NaH in 4 portions and warmed up to room temperature during 7 h. The reaction was cooled to 0° C. and treated with 500 ml aqueous saturated NH4Cl solution, extracted with EtOAc (3×). The organic phase was washed with 10% NaCl dried over Na2SO4 and evaporated. Flash column chromatography on silica gel with hexane/EtOAc (9:1 to 8.5:1.5) gave 9.37 g (46%) of (2S,4R)-2-(2,4,5-trifluoro-benzyloxymethyl)-4-tritylsulfanyl-pyrrolidine-1-carboxylic acid tert-butyl ester, MS: 620 (MH+).

Provenance & Evidence