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To a solution of 88 (240 mg, 1.45 mmol) in 7:3 CH2Cl2:MeOH (10 mL) was added TMS Diazomethane (2.0 M in hexanes) (0.9 mL, 1.8 mmol) in 0.2 ml aliquots until the color remained yellow. The reaction was allowed to stir for an additional 0.25 hours at room temperature. After stirring, glacial acetic acid was added dropwise until the solution became colorless. The reaction was concentrated in vacuo to an oil which was purified by flash chromatography on silica gel using ether:petroleum ether (1:9) to yield 89 (210 mg, 80%) as a clear oil. 1H NMR (CDCl3) δ 3.60 (s, 3H), 2.25-2.13 (m, 1 H), 2.08-1.94 (m, 3 H), 1.95-1.90 (m, 2 H), 1.49-1.31 (m, 3 H), 1.10-0.93 (m, 2 H); 13C NMR (CDCl3) δ 176.7, 83.3, 69.8, 51.9, 43.4, 36.7, 31.9, 29.2, 26.3; APCI m/z (rel intensity) 181 (MH+, 100).

1. stirringAfter stirring
2. concentrationThe reaction was concentrated in vacuo to an oil which
3. customwas purified by flash chromatography on silica gel