[CH3:1][O:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[S:9][C:10]1[CH:19]=[CH:18][CH:17]=[CH:16][C:11]=1[C:12]([O:14][CH3:15])=[O:13].[CH3:20][O:21]C(Cl)Cl>ClCCCl.[Ti](Cl)(Cl)(Cl)Cl>[C:12]([C:11]1[CH:16]=[CH:17][CH:18]=[CH:19][C:10]=1[S:9][C:4]1[CH:5]=[C:6]([CH:7]=[CH:8][C:3]=1[O:2][CH3:1])[CH:20]=[O:21])([O:14][CH3:15])=[O:13]Dissolve 117 g (0.427 mole) of the ester of Step B in 1500 ml of 1,2-dichloroethane and cool with stirring in an ice-bath. Add 200 ml (345 g, 1.82 mole) of titanium tetrachloride at a rapid dropwise rate. Add also fairly rapidly 154 g (1.34 mole) of dichloromethyl methyl ether. Stir the mixture under a nitrogen atmosphere overnight then pour into ice. After shaking, separate the organic phase and extract the aqueous phase twice with methylene chloride. Wash the combined organic phases twice with water, dry and strip to an oil which crystallizes. (m.p. 99°-104° C.).
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