[C:1]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[S:15][CH2:16][C:17]([CH2:24][CH3:25])([CH2:20][CH2:21][CH2:22][CH3:23])[CH:18]=O)(=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1>COCCOC.[Cl-].[Na+].O.[Zn]>[CH2:20]([C:17]1([CH2:24][CH3:25])[CH:18]=[C:1]([C:2]2[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=2)[C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=2[S:15][CH2:16]1)[CH2:21][CH2:22][CH3:23]A mixture of 2.6 g (0.04 mole) of zinc dust, 7.2 g (0.047 mole) of TiCl3 and 80 mL of anhydrous ethylene glycol dimethyl ether (DME) was held at reflux for 2 h. The reaction mixture was cooled to 5° C. To the reaction mixture was added dropwise a solution of 3.54 g (0.01 mole) of 2 in 30 mL of DME in 40 min. The reaction mixture was stirred at room temperature for 16 h and then was held at reflux for 2 h and cooled before being poured into brine. The organic was extract into methylene chloride. The methylene chloride extract was dried over MgSO4 and concentrated in vacuo. The residue was purified by HPLC (hexane) to give 1.7 g (43%) of 3 as an oil in the first fraction. The second fraction was discarded and the third fraction was further purified by HPLC (hexane) to give 0.07 g (2%) of 4a in the earlier fraction and 0.1 g (3%) of 4b in the later fraction.
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