[CH:1]([C@H:3]1[CH2:7][CH2:6][N:5]([C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9])[CH2:4]1)=[O:2].[Cl:15][C:16]1[CH:17]=[C:18]([Mg]Br)[CH:19]=[CH:20][C:21]=1[F:22]>C1COCC1>[Cl:15][C:16]1[CH:17]=[C:18]([CH:1]([OH:2])[C@H:3]2[CH2:7][CH2:6][N:5]([C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9])[CH2:4]2)[CH:19]=[CH:20][C:21]=1[F:22]To a stirred solution of (S)-tert-butyl 3-formylpyrrolidine-1-carboxylate (67)(367.3 mg, 1.843 mmol) in THF (9.2 mL, 0.2 M) under nitrogen atmosphere cooled to 0° C. and degassed with N2 was added dropwise a THF solution of (3-chloro-4-fluorophenyl)magnesium bromide (4056 μL, 2.028 mmol) and the solution stirred at 0° C. for 3 h. The reaction was then quenched by addition of water (3 mL) THF was removed by rotovap, and the mixture was extracted with EtOAc (2×30 mL). The combined organics were washed with water (2×30 mL) and brine (1×30 mL). The organic extracts were dried (Na2SO4), filtered and concentrated. The crude product was loaded onto an SP1 samplet and purified by chromatography eluting a DCM/acetone gradient (2 to 45% acetone) to afford 364 mg (60%) of 69a/69b as an approximate 1:1 mixture of diastereomers as a clear oil which was used without additional purification.
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