[OH:1][C:2]([CH3:7])([CH3:6])[C:3](=[O:5])[CH3:4].[C:8](OC(=O)C)(=[O:10])[CH3:9].CCN(CC)CC.Cl>CN(C1C=CN=CC=1)C.C(Cl)Cl>[C:8]([O:1][C:2]([CH3:7])([CH3:6])[C:3](=[O:5])[CH3:4])(=[O:10])[CH3:9]A mechanically stirred 3 l round-bottomed flask under an atmosphere of nitrogen was charged with 3-hydroxy-3-methyl-2-butanone (100.0 g, 979 mmol) and CH2Cl2 (900 ml). A solution of acetic anhydride (92.4 ml, 979 mmol) and CH2Cl2 (50 ml) was added over 10 min and the resulting solution was cooled to 10° C. DMAP (5.98 g, 49 mmol) was added in one portion followed by Et3N (205 ml, 1.47 mol) over 50 min while maintaining an internal temperature below 16° C. After the addition, the mixture was aged for 16 h at room temperature. The resulting solution was poured onto MeOH (200 ml) and after 15 min 2N HCl (400 ml) was added. The phases were separated and the organic phase was washed with water (500 ml) then saturated NaHCO3 (500 ml) then dried over Na2SO4. The solvent was removed under diminished pressure to provide 3-acetoxy-3-methyl-2-butanone as a golden oil (132.5 g): 1H NMR (CDCl3, 400 MHz) δ 2.12 (3H, s), 2.09 (3H, s), 1.47 (6H, s); 13C NMR (CDCl3, 100.61 MHz) δ 206.6, 170.2, 83.5, 23.4, 23.2, 21.0.
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