[OH:1][C:2]1[CH:18]=[CH:17][C:5]([CH2:6][C@H:7]2[CH2:12][CH2:11][C:10]3[CH:13]=[CH:14][CH:15]=[CH:16][C:9]=3[O:8]2)=[CH:4][CH:3]=1.C(N(CC)CC)C.[C:26](OC(=O)C)(=[O:28])[CH3:27]>CN(C)C1C=CN=CC=1.C(Cl)Cl>[C:26]([O:1][C:2]1[CH:18]=[CH:17][C:5]([CH2:6][C@H:7]2[CH2:12][CH2:11][C:10]3[CH:13]=[CH:14][CH:15]=[CH:16][C:9]=3[O:8]2)=[CH:4][CH:3]=1)(=[O:28])[CH3:27](R)-(-)-3,4-Dihydro-2-(4-hydroxybenzyl)-2H-benzopyran (5.0 g, 20 mmol), 4-dimethylaminopyridine (240 mg, 2 mmol), triethylamine (2.6 g, 25 mmol) and acetic anhydride (2.9 g, 28 mmol) were dissolved in methylene chloride (75 ml) and stirred at room temperature for 2 hours under a nitrogen atmosphere. The solvent was removed in vacuo and the residue purified on silica gel using hexanes/ethyl acetate (3:1) as eluent to afford an oil which was crystallized from hexanes to yield 4.0 g of the title product, m.p. 64°-65° C.; [α]D -98.9° (c 1.3, MeOH);
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