[CH2:1]([O:3][C:4](=[O:26])[C:5]([CH3:25])([CH3:24])[CH2:6][CH2:7][CH2:8][CH2:9][C:10](=[O:23])[CH2:11][CH2:12][CH2:13][CH2:14][C:15]([CH3:22])([CH3:21])[C:16]([O:18][CH2:19][CH3:20])=[O:17])[CH3:2].[BH4-].[Na+].O>CO>[CH2:19]([O:18][C:16](=[O:17])[C:15]([CH3:21])([CH3:22])[CH2:14][CH2:13][CH2:12][CH2:11][CH:10]([OH:23])[CH2:9][CH2:8][CH2:7][CH2:6][C:5]([CH3:25])([CH3:24])[C:4]([O:3][CH2:1][CH3:2])=[O:26])[CH3:20]7-Oxo-2,2,12,12-tetramethyltridecanedioic acid diethyl ester (9.2 g, 25 mmol) was dissolved in methanol (200 mL) and the solution was cooled in an ice-water bath. Sodium borohydride (0.95 g, 25 mmol) was added. After 2 h, another portion of sodium borohydride (0.95 g, 25 mmol) was added and stirring was continued for 2 h. The reaction mixture was hydrolyzed with water (200 mL). The aqueous solution was extracted with dichloromethane (3×150 mL). The combined organic layers were dried over magnesium sulfate and concentrated in vacuo to give the product (8.5 g, 92%) as an oil. 1H NMR (300 MHz, CDCl3/TMS): δ (ppm): 4.11 (q, 4H, J=7.0 Hz), 3.60-3.50 (m, 1H), 1.66-1.32 (m, 11H), 1.24 (pseudo-t, 12H, J=7.0 Hz), 1.15 (s, 12H). 13C NMR (75 MHz, CDCl3/TMS): δ (ppm): 178.0, 71.7, 60.1, 42.1, 40.6, 37.3, 26.0, 25.1, 24.9, 14.2. HRMS (LSIMS, nba): Calcd. for C21H41O3 (MH+): 373.2954, found: 373.2936. HPLC: 88.90% purity.
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