[CH3:1][C:2]1([CH3:20])[CH:11]=[C:10]([C:12]2[CH:17]=[CH:16][C:15]([CH3:18])=[CH:14][CH:13]=2)[C:9]2[C:4](=[CH:5][CH:6]=[C:7](Br)[CH:8]=2)[S:3]1.[Li]CCCC.CN([CH:29]=[O:30])C>C1COCC1.CCCCCC>[CH3:1][C:2]1([CH3:20])[CH:11]=[C:10]([C:12]2[CH:17]=[CH:16][C:15]([CH3:18])=[CH:14][CH:13]=2)[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([CH:29]=[O:30])[CH:8]=2)[S:3]1To a cold (−78° C.) solution of 2,2-dimethyl-4(tol-4-yl)-6-bromo-thiochrom-3-ene (Compound N, 280 mg, 0.81 mmol) in THF (5 mL) was added n-BuLi in hexane (1.6 M solution, 0.66 mL). The mixture was gradually warmed to −10° C. over 25 min. and recooled to −78° C. To this solution was added DMF (80 mg, 1.1 mmol) and stirred at ambient temperature for 5 hours. The reaction was quenched by adding water (10 mL), ethyl acetate (100 mL), and the organic layer was washed with brine (10 mL), dried and the solvent removed by distillation. The crude material was used in the next reaction without further purification.
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