[Li]CCCC.C(NC(C)C)(C)C.[Br:13][C:14]1[CH:15]=[N:16][CH:17]=[C:18]([F:20])[CH:19]=1.[CH3:21][C:22]([CH3:24])=[O:23]>C1COCC1>[Br:13][C:14]1[CH:15]=[N:16][CH:17]=[C:18]([F:20])[C:19]=1[C:22]([OH:23])([CH3:24])[CH3:21]n-BuLi 1.6M in hexanes (11.25 ml, 18.00 mmol) was added dropwise to a solution of diisopropylamine (2.78 ml, 19.50 mmol) in THF (50.0 ml) at −78° C. under N2. The resulting mixture was warmed up to −40° C. and stirred for 10 min and recooled to −78° C. 3-bromo-5-fluoropyridine (2.64 g, 15 mmol) in 5 mL THF was added dropwise at this temperature. After 30 min, acetone (3.30 ml, 45.0 mmol) was added dropwise and the resulting mixture was stirred for 30 min at −78° C., and then for another 30 min at 0° C. The mixture was quenched with saturated NH4Cl and extracted with EtOAc two times, dried over magnesium sulfate, filtered, concentrated. The residue was purified via Biotage (0-30% AcOEt/heptane, SNAP50) giving 10a (1.691 g, 48%) as a yellow oil. LC-MS (M+1) 235.9, t=1.18 min.
読み込み中…