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To a solution of 960 mg (6.31 mmol) of 86 in 6 mL DMF was added 0.62 mL (7.57 mmol) pyridine and 0.78 mL (8.27 mmol) acetic anhydride. The reaction was allowed to stir overnight at room temperature. After 16 hours, starting material still remained. The reaction mixture was heated at 75° C. for 3 hours. The solvent was removed under reduced pressure to yield a yellow oil which was purified by flash chromatography, on silica gel, eluting with 1:3 ether/petroleum ether to yield 1.12 g (91%) of 87 as an oil. 1H NMR (CDCl3) δ 3.87 (d, J=6.2 Hz, 2H), 2.06 (d, J=4.3 Hz, 2H), 2.03 (s, 3H), 1.98-1.93 (m, 1H), 1.92-1.83 (m, 2H), 1.83-1.74 (m, 2H), 1.63-1.36 (m, 2H), 1.12-0.90 (m, 4H); 13C NMR (CDCl3) δ 171.7, 83.7, 69.9, 69.6, 37.4, 37.3, 32.1, 29.7, 26.5, 21.4; APCI m/z (rel intensity) 195 (M+, 30), 153 (M+, 70), 135 (M+, 100).

1. waitAfter 16 hours
2. temperatureThe reaction mixture was heated at 75° C. for 3 hours
3. customThe solvent was removed under reduced pressure
4. customto yield a yellow oil which
5. customwas purified by flash chromatography, on silica gel
6. washeluting with 1:3 ether/petroleum ether