[Br:1][C:2]1[CH:7]=[C:6]([CH3:8])[C:5]([C:9]2[C:10](=[O:16])[CH2:11][CH2:12][C:13]=2[O:14][CH3:15])=[C:4]([CH3:17])[CH:3]=1.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH2:28]1[CH2:33][CH2:32][CH:31]([CH:34]=[O:35])[CH2:30][CH2:29]1>O1CCCC1>[Br:1][C:2]1[CH:3]=[C:4]([CH3:17])[C:5]([C:9]2[C:10](=[O:16])[CH:11]([CH:34]([CH:31]3[CH2:32][CH2:33][CH2:28][CH2:29][CH2:30]3)[OH:35])[CH2:12][C:13]=2[O:14][CH3:15])=[C:6]([CH3:8])[CH:7]=1To a solution of 2-(4-bromo-2,6-dimethyl-phenyl)-3-methoxy-cyclopent-2-enone (1 g, 3.4 mmol) in 10 ml of dry tetrahydrofuran under nitrogen atmosphere at −78° C. LiHMDS (4.42 ml, 4.42 mmol) is added slowly and it is stirred at −78° C. for 40 minutes. A solution of cyclohexyl carboxaldehyde (761 mg, 6.8 mmol) in dry tetrahydrofuran (10 ml) is added to the reaction mixture at −78° C. The reaction mixture is stirred at this temperature for 2 hours and then at room temperature for 3 hours. The reaction mixture is quenched with water (50 ml) and the aqueous layer is extracted with ethyl acetate (3*100 ml). The combined organic layers are dried with sodium sulfate and concentrated under vacuum to obtain crude product which is directly taken to the next step without further purification.
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