[CH3:1][C:2]1[CH:6]=[CH:5][S:4][C:3]=1[CH:7]1[O:11][CH2:10][CH2:9][O:8]1.C([Li])CCC.[CH2:17]([Sn:21](Cl)([CH2:26][CH2:27][CH2:28][CH3:29])[CH2:22][CH2:23][CH2:24][CH3:25])[CH2:18][CH2:19][CH3:20]>O1CCCC1.C(OCC)C>[CH2:26]([Sn:21]([CH2:17][CH2:18][CH2:19][CH3:20])([CH2:22][CH2:23][CH2:24][CH3:25])[C:5]1[S:4][C:3]([CH:7]2[O:11][CH2:10][CH2:9][O:8]2)=[C:2]([CH3:1])[CH:6]=1)[CH2:27][CH2:28][CH3:29]A mixture of 2-(3-methylthien-2-yl)-1,3-dioxolane (intermediate 75, 1.5 g) in tetrahydrofuran (50 ml), stirred at −60° C. under a nitrogen atmosphere, was treated drop-wise with 1.6M n-butyl lithium in hexanes (6.1 ml). The reaction mixture was stirred at this temperature for 1 hour and tributyltin chloride (2.6 ml) was added; stirring was continued at −60° C. for 1 hour and then the reaction allowed to warm to ambient temperature. After 18 hours the reaction mixture was diluted with diethylether and this mixture was extracted with water and the ether layer dried with brine and over magnesium sulfate. The product isolated after evaporation of the solvent was further purified by flash column chromatography using cyclohexane:ethyl acetate (50:1) as eluent to give the title compound as a yellow oil.
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