[Li]CCCC.Br[C:7]1[CH:8]=[N:9][CH:10]=[CH:11][CH:12]=1.[CH2:13]1[O:23][C:16]2([CH2:21][CH2:20][C:19](=[O:22])[CH2:18][CH2:17]2)[O:15][CH2:14]1>CCOCC.C1COCC1>[CH2:14]1[O:15][C:16]2([CH2:21][CH2:20][C:19]([OH:22])([C:7]3[CH:8]=[N:9][CH:10]=[CH:11][CH:12]=3)[CH2:18][CH2:17]2)[O:23][CH2:13]1To a solution of n-BuLi (2.5 M in hexanes, 88.4 mL, 221.0 mmol) in Et2O (250 mL) at −78° C. was added a chilled solution (−78° C.) of 3-bromopyridine (35 g, 221.0 mmol) in Et2O (125 mL) via cannula. After being stirred for 10 min, a solution of 1,4-cyclohexanedione monoethylene ketal (34.5 g, 221.0 mmol) in THF (125 mL) was added via cannula The reaction mixture was stirred for 1 h at −78° C., then slowly warmed to −20° C. over 1 h. The reaction was quenched by pouring into saturated aqueous NH4Cl, and the layers were separated. The aqueous layer was extracted with CH2Cl2 (100 mL×3) and the combined organic layers were washed with brine (200 mL), dried with MgSO4 and concentrated in vacuo. The crude product was triturated with Et2O to afford 4-hydroxy-4-(3-pyridyl)cyclohexanone ethylene ketal as a white solid.
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