[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 1L 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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