[Si:1]([O:8][CH2:9][C@@H:10]1[CH:15]=[C:14]([CH2:16][OH:17])[C:13](=[O:18])[CH2:12][N:11]1[C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].[CH3:26]N(C)C1C2C(=CC=CC=2N(C)C)C=CC=1.F[B-](F)(F)F.C[O+](C)C>C(Cl)Cl>[Si:1]([O:8][CH2:9][C@@H:10]1[CH:15]=[C:14]([CH2:16][O:17][CH3:26])[C:13](=[O:18])[CH2:12][N:11]1[C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]To a stirred solution of (S)-tert-butyl 2-((tert-butyldimethylsilyloxy)methyl)-4-(hydroxymethyl)-5-oxo-5,6-dihydropyridine-1(2H)-carboxylate (17.37 g, 46.75 mmol) in DCM (480 mL) was added N1,N1,N8,N8-tetramethylnaphthalene-1,8-diamine (60.1 g, 280.51 mmol). Then it was cooled to 0° C. and trimethyloxonium tetrafluoroborate (20.74 g, 140.25 mmol) was added. It was then stirred at rt for 6 h. Then it was concentrated under reduced pressure. The residue was then taken up in 100 mL Et2O and filtered, washed with 400 mL Et2O. The organic layer was then washed with 10% citric acid, aq. NaHCO3, brine, dried over MgSO4, filtered and concentrated to afford the desired product (16.73 g, 93%) as an oil.
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