[CH2:1]([O:8][C:9]1[CH:14]=[CH:13][C:12]([OH:15])=[C:11]([CH:16]([OH:23])[C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[CH:10]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([O-])([O-])=O.[Cs+].[Cs+].Br[C:31]([CH3:38])([CH3:37])[C:32]([O:34][CH2:35][CH3:36])=[O:33]>CN(C=O)C>[CH2:35]([O:34][C:32](=[O:33])[C:31]([O:15][C:12]1[CH:13]=[CH:14][C:9]([O:8][CH2:1][C:2]2[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=2)=[CH:10][C:11]=1[CH:16]([OH:23])[C:17]1[CH:18]=[CH:19][CH:20]=[CH:21][CH:22]=1)([CH3:38])[CH3:37])[CH3:36]4-Benzyloxy-2-(hydroxy-phenyl-methyl)-phenol (690 mg, 2.25 mmol) and Cs2CO3 (734 mg, 2.25 mmol) in DMF (7 mL) was treated with ethyl bromoisobutyrate (0.66 mL, 4.5 mmol) and heated at 55° C. for 16 h. Additional bromo ester (0.40 mL, 1.23 mmol) and CS2CO3 (400 mg, 1.23 mmol) were added and the reaction mixture was heated for 40 h. The mixture was cooled and partitioned between EtOAc (30 mL) and H2O (10 mL). The organic layer was washed with brine (10 mL), dried (Na2SO4), and concentrated. The crude product was purified by flash chromatography using hexanes:ethyl acetate to give a pale yellow oil (615 mg, 65%): 1H NMR (400 MHz, CDCl3) δ 1.21 (t, 3H, J=7.3 Hz), 1.39 (s, 3H), 1.43 (s, 3H), 4.19 (q, 2H, J=7.3 Hz), 4.97 (s 2H), 6.00 (s, 1H), 6.61 (d, 1H, J=8.8 Hz), 6.74 (dd, 2H, J=3.2, 9.0 Hz), 6.96 (d, 1H, J=2.9 Hz), 7.22-7.39 (m, 10).
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