[OH:1][CH:2]([CH2:6][CH2:7][CH2:8][CH3:9])[C:3]([OH:5])=[O:4].Br[CH:11]([CH3:15])[C:12](Br)=[O:13].C(N(CC)CC)C>CC(C)=O>[CH3:15][CH:11]1[O:4][C:3](=[O:5])[CH:2]([CH2:6][CH2:7][CH2:8][CH3:9])[O:1][C:12]1=[O:13]2.5 g 2-hydroxyhexanoic acid (18.9 mmol) and 2.1 mL 2-bromopropionyl bromide (19.7 mmol) were stirred at 75° C. under nitrogen for 12 h. 150 mL acetone and 5.3 mL anhydrous triethylamine (38 mmol) were added to the mixture and the solution was stirred for 3 h at 60° C. After filtration of the triethylammonium bromide salts, acetone was distilled off and the resulting mixture was dissolved in 300 mL ethyl acetate:hexane mixture (1:2). After filtration over silica gel the solvents were distilled off, and the remaining crude product was recrystallized from hexane. 1H NMR (500 MHz, CDCl3): δ 5.05 (q, 1H), 4.90 (dd, 1H), 1.9-2.15 (br m, 2H), 1.68 (d), 1.65 (d), (3H, of 2 diastereoisomers), 1.3-1.6 (br m, 4H), 0.93 (t, 3H). 13C NMR (500 MHz, CDCl3): δ 167.54, 166.93, 166.25, 165.85, 75.79, 72.50, 72.24, 31.61, 29.70, 26.69, 26.42, 22.19, 21.97, 17.52, 15.81, 13.72, 13.66. ELEM. ANAL. Calcd. for C9H14O4: C, 58.06; H, 7.53. Found: C, 57.62; H, 7.60. Yield: 40%.
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