Sodium hydride → (3S,4S)-3-[(5-chloro-thiophene-2-carbonyl)-amino]-4-(2,2-difluoro-ethoxy)-pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

30.1 A suspension of 37 mg NaH (55% in oil) in 2 ml DMF was treated at 0° C. under an argon atmosphere with a solution of 270 mg (3S,4S)-3-[(5-chloro-thiophene-2-carbonyl)-amino]-4-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester (example 22.4). The reaction mixture was stirred for 1 hr at r.t. Then, 334 mg 2,2-difluoroethyl trifluoromethanesulfonate were added at 0° C. The reaction mixture was stirred for 2 days at r.t., then diluted with EtOAc and washed with water. The organic layer was dried over MgSO4, filtered and concentrated. The crude product was isolated by chromatography (silica gel; gradient: cyclohexane->cyclohexane/EtOAc 9:1) to give 157 mg (3S,4S)-3-[(5-chloro-thiophene-2-carbonyl)-amino]-4-(2,2-difluoro-ethoxy)-pyrrolidine-1-carboxylic acid tert-butyl ester. Colorless solid. MS 409.0 ([M+H]+)

Provenance & Evidence