[Br:1][C:2]1[CH:3]=[CH:4][C:5]([N:8]2[CH2:12][CH2:11][C@@H:10]([NH2:13])[CH2:9]2)=[N:6][CH:7]=1.C(O[C:17]1(O[Si](C)(C)C)[CH2:19][CH2:18]1)C.[CH3:25][C:26](O)=O.[BH3-][C:30]#N.[Na+]>CO>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([N:8]2[CH2:12][CH2:11][C@@H:10]([N:13]([CH:17]3[CH2:18][CH2:19]3)[CH:26]3[CH2:25][CH2:30]3)[CH2:9]2)=[N:6][CH:7]=1
Dissolve (R)-1-(5-bromo-pyridin-2-yl)-pyrrolidin-3-ylamine (1.60 g, 6.63 mmol) in CH3OH (915 mL). Add (1-ethoxy-cyclopropoxy)-trimethyl-silane (2.7 mL, 13.49 mmol) and HOAc (1.9 mL, 33.15 mmol) and stir at RT for 3 h. Add NaBH3CN (4.2 g, 66.30 mmol) and reflux overnight. Cool the mixture to 0° C., quench with 2.0 M NaOH (15 mL), and dilute with H2O (100 mL). Extract with EtOAc (3×100 mL). Wash the combined organic layers with 1.0 M NaOH (50 mL), H2O (100 mL), and brine (50 mL). Dry the solution with Na2SO4, filter, and concentrate. Purify the crude material by chromatography, eluting with 0.5% Et3N, 5% CH3OH and 95% CHCl3 to give 1.20 g (56%) of the title compound. MS/ES m/z (79Br) 322 [M+H]+.
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