[C:1]([O:7][CH2:8][CH3:9])(=[O:6])[CH2:2][C:3]([O-:5])=O.N1C=C[CH:13]=[CH:12][C:11]=1[C:16]1C=CC=CN=1.C([Li])CCC.CC(CC)C(Cl)=O.Cl>O1CCCC1>[CH3:16][CH:11]([CH2:12][CH3:13])[C:3](=[O:5])[CH2:2][C:1]([O:7][CH2:8][CH3:9])=[O:6]
To a solution of monoethyl malonate (49.5 mL, 0.42 mol) and a few milligrams of 2,2′-bipyridyl in tetrahydrofuran at −70° C. was added 2.5 M n-butyl lithium in hexanes (0.34 L, 0.84 mol) dropwise over approximately 1.5 hours. Then 2-methylbutyryl chloride (26 mL, 0.21 mol) was added dropwise. The mixture was allowed to warm to ambient temperature and was then poured into 1 N hydrochloric acid. The mixture was extracted three times with ether and the combined organic layers were dried over magnesium sulfate and concentrated. The resulting oil was purified by vacuum distillation (boiling range 75-85° C.) to afford ethyl 4-methyl-3-oxohexanoate (36.4 g, 100%). 1H-NMR (400 MHz, DMSO-d6) δ 4.06 (q, J=7 Hz, 2H), 3.60 (s, 2H), 2.57-2.49 (m, 1H), 1.64-1.53 (m, 1H), 1.36-1.26 (m, 1H), 1.15 (t, J=7 Hz, 3H), 0.97 (d, J=7 Hz, 3H), 0.78 (t, J=7 Hz, 3H).
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