[F:1][C:2]([F:8])([F:7])[C:3]([O:5][CH3:6])=[O:4].Cl[CH2:10][CH2:11][OH:12].CS(C)=O.[H-].[Na+]>O>[CH3:6][O:5][C:3]1([C:2]([F:8])([F:7])[F:1])[O:12][CH2:11][CH2:10][O:4]1A mixture of 42.0 g (0.33 mol) of methyl trifluoroacetate, 26.6 g (0.33 mol) of 2-chloroethanol, and 150 mL of dimethylsulfoxide (DMSO) was stirred at 10°-20° while 15.8 g (0.33 mol) of 50% NaH in mineral oil was added portionwise. The resulting mixture was stirred at 20° for 2 h, at 25° for several days, and then poured into 1 L of water. The resulting aqueous layer was extracted with 100 mL of ether. The organic layers were combined, then washed twice with water, dried over CaSO4, and distilled to give 35.6 g (63% yield) of 2-methoxy-2-trifluoromethyl-1,3-dioxolane, b.p. 60°-65° at 3.3 kPa (25 mm), and a residue containing about 4.8 g (7% yield) of by-product 2-(2-chloroethoxy)-2-trifluoromethyl-1,3-dioxolane (estimated by GC).
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