Br[C:2]1[S:3][C:4](Br)=[C:5]([Br:13])[C:6]=1[CH2:7][CH2:8][CH2:9][CH2:10][CH2:11][CH3:12].C1COCC1.C([Li])CCC>O>[Br:13][C:5]1[C:6]([CH2:7][CH2:8][CH2:9][CH2:10][CH2:11][CH3:12])=[CH:2][S:3][CH:4]=1Compound 51 (70 g, 0.173 mol) is mixed with dry THF (400 mL). To this mixture, n-butyllithium (138 mL, 2.5M in hexane, 0.345 mol) is added dropwise at −78° C. under argon. The resulting mixture is stirred for 10 minutes, then water (30 mL) is added to quench the reaction. The THF is evaporated and the organic is extracted with ethyl acetate (2×100 mL). The combined organic layers are washed with brine (2×100 mL), water (70 mL) and dried over MgSO4. After evaporation of the solvent, the resulting crude product is purified by vacuum distillation (72-74° C. at 0.17 mbar) to yield 52 (35.3 g, 82.6% yield). GC/MS: 246 g/mol (M−1). 1H NMR (CD2Cl2): δ 7.22 (s, 1H), 6.96 (s, 1H), 2.57 (t, 2H), 1.61 (m, 2H), 1.32 (m, 6H), 0.88 (t, 3H). 13C NMR: 141.92, 122.87, 120.95, 112.89, 31.88, 30.07, 29.53, 29.20, 22.88, 14.14.
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