[Cl:1][C:2]1[CH:14]=[CH:13][C:12]([N+:15]([O-:17])=[O:16])=[CH:11][C:3]=1[O:4][CH2:5][C@@H:6]1[CH2:10][CH2:9][CH2:8][NH:7]1.C=O.[BH3-][C:21]#N.[Na+].CC(O)=O>CC#N>[Cl:1][C:2]1[CH:14]=[CH:13][C:12]([N+:15]([O-:17])=[O:16])=[CH:11][C:3]=1[O:4][CH2:5][C@@H:6]1[CH2:10][CH2:9][CH2:8][N:7]1[CH3:21]To (S)-2-(2-chloro-5-nitro-phenoxymethyl)-pyrrolidine (4.82 g, 18.77 mmol) in 167 mL CH3CN at RT was added 37% aqueous formaldehyde (7.58 mL) then NaCNBH3 (1.887 g, 30.03 mmol). The reaction was stirred for 1 h, as the reaction pH was adjusted every 10 min to about 7 by adding small amounts of HOAc. The reaction was concentrated to small aqueous volume and dissolved in 2 N NaOH (aq) and Et2O. The layers were separated, and the organic layer was washed twice with 2 N NaOH then extracted twice with 1 N HCl (aq). The combined acidic aqueous layers were basified to pH>12 with solid NaOH and extracted 3 times with EtOAc. The EtOAc layers were washed once with 2 N NaOH and then once with mix of brine and 2 N NaOH, combined, dried over Na2SO4, filtered, and concentrated to dryness, to yield the title compound.
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