Br[CH2:2][CH:3]1[CH:7]([CH2:8]Br)[O:6][C:5](=O)[O:4]1.N12CCCNC1C=CCC[CH2:12]2.[CH2:22]([OH:24])[CH3:23].C(OCC)C.CCCCCC>C(Cl)Cl>[CH2:7]([O:6][C:5]([O:4][CH2:3][CH3:2])([CH3:12])[C:22](=[O:24])[CH3:23])[CH3:8]
A mixture of 4,5-dibromomethyl-1,3-dioxolan-2-one (2.07 g, 7.6 mmole) and 1,8-diazabicyclo[5.4.0]undec-5-ene (2.26 ml, 15.2 mmole) in CH2Cl2 (20 ml) was stirred at 20° C. for 5 h, then anhydrous ethanol (5.0 ml, 85 mmole) was added, and the resulting mixture was stirred at 20° C. for 10 h. Flash chromatography (ethyl ether-hexane eluent) of the reaction mixture yielded 3,3-diethoxy-2-butanone as a colorless liquid (110 mg, 10%): IR (AgCl) 2965, 1722, 1350, 1253, 1133, 1050, 954 cm-1 ; 'H NMR (CDCl3) 1.23 (m, 9 H), 2.28 (s, 3 H), 3.50(q, J=7.5 Hz, 4 H).
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