[Br:1][C:2]1[CH:7]=[C:6]([O:8][CH3:9])[C:5]([O:10][CH:11]([CH3:13])[CH3:12])=[CH:4][C:3]=1[CH:14]([OH:16])[CH3:15].CC(OI1(OC(C)=O)(OC(C)=O)OC(=O)C2C=CC=CC1=2)=O>C(Cl)Cl>[Br:1][C:2]1[CH:7]=[C:6]([O:8][CH3:9])[C:5]([O:10][CH:11]([CH3:13])[CH3:12])=[CH:4][C:3]=1[C:14](=[O:16])[CH3:15]A magnetically stirred solution of alcohol 37 (520 mg, 1.80 mmol) in CH2Cl2 (10 mL), maintained at 0° C. was treated with Dess-Martin periodinane (1.14 g, 2.69 mmol). The resulting mixture was warmed to 18° C., stirred at this temperature for 2 h then concentrated, under reduced pressure, onto TLC-grade silica (ca. 500 mg). The resulting free-flowing solid was subjected to flash chromatography (1:19 v/v ethyl acetate/hexane elution) to afford the title compound 38 (361 mg, 70%) as a pale-yellow solid, m.p. 59.0-59.9° C., Rf 0.6 in 1:1 v/v ethyl acetate/hexane.
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