Br[C:2]1[CH:7]=[CH:6][C:5]([C:8]([CH3:12])([CH3:11])[C:9]#[N:10])=[CH:4][C:3]=1[CH3:13].[CH2:14]([Li])CCC.CON(C)[C:22](=[O:24])[CH3:23]>C1COCC1.[Cl-].[Na+].O>[C:22]([C:2]1[CH:7]=[CH:6][C:5]([C:8]([CH3:12])([CH3:11])[C:9]#[N:10])=[CH:4][C:3]=1[CH3:13])(=[O:24])[CH3:23].[C:22]([C:2]1[CH:3]=[CH:4][C:5]([C:8]([CH3:11])([CH3:12])[C:9]#[N:10])=[C:6]([CH3:14])[CH:7]=1)(=[O:24])[CH3:23]
To a stirred solution of 2-(4-bromo-3-methylphenyl)-2-methylpropanenitrile (5.0 g, 21.0 mmol) in anhydrous THF (75 mL) at −100° C. is added n-butyllithium (2 M in c-hexane) (21 mL, 42 mmol). This reaction mixture is stirred at that temperature 5 min., then N-methoxy-N-methyl-acetamide (4.33 g, 42 mmol) is added. The solution is then warmed up to room temperature over 1 h. Acidic brine (30 mL of brine, 15 mL of 3% HCl aq) is then slowly added and the solution is extracted with EtOAc (3×100 mL). The organic layer is dried over MgSO4, filtered and concentrated under reduced pressure. The crude product is purified on silica gel using a 0 to 30% gradient of EtOAc in heptane to provide the expected product 2-(4-acetyl-2-methylphenyl)-2-methylpropanenitrile (1.0 g, 24%). 1H NMR (400 MHz, CHLOROFORM-D) δ ppm 1.71 (s, 6H) 2.53 (s, 3H) 2.56 (s, 3H) 7.30-7.38 (m, 2H) 7.70 (d, J=8.01 Hz, 1H)
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