[Cl:1][C:2]1[N:7]=[C:6]([CH3:8])[CH:5]=[CH:4][CH:3]=1.C([Li])CCC.[C:14](=O)([O:18]CC)[O:15][CH2:16][CH3:17]>C1COCC1>[CH2:16]([O:15][C:14](=[O:18])[CH2:8][C:6]1[CH:5]=[CH:4][CH:3]=[C:2]([Cl:1])[N:7]=1)[CH3:17]To a solution of 6-chloro-2-picoline (2.0 g, 15.7 mmol) in THF (60 mL) at −20° C. was added n-butyllithium (2.5M in hexanes, 9.4 mL, 23.5 mmol). The resulting dark red solution was stirred at −20° C. for 15 minutes, then cooled to −78° C. and diethyl carbonate (2.85 mL, 23.5 mmol) was added dropwise. The reaction mixture was stirred at −78° C. for 30 minutes then slowly warmed to r.t. overnight. The reaction mixture was quenched with sat. aqueous ammonium chloride solution (100 mL) and extracted with EtOAc (3×60 mL). The combined organic fractions were washed with brine (60 mL), dried (MgSO4) and concentrated in vacuo. Purification by column chromatography (SiO2, 0-40% EtOAc/heptane, followed by SiO2, 20% EtOAc/heptane) gave the title compound (120 mg, 25%) as a pale yellow oil. LCMS (ES+) 321.11 (M+H)+, RT 4.43 min (Method 1).
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