Br[C:2]1[CH:21]=[CH:20][C:19]([O:22][CH3:23])=[CH:18][C:3]=1[O:4][CH2:5][CH:6]1[CH:10]=[CH:9][CH2:8][N:7]1[C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12].C([SnH](CCCC)CCCC)CCC.C1CCN2C(=NCCC2)CC1>C1(C)C=CC=CC=1>[CH3:23][O:22][C:19]1[CH:20]=[CH:21][C:2]2[CH:10]3[CH:6]([N:7]([C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])[CH2:8][CH2:9]3)[CH2:5][O:4][C:3]=2[CH:18]=1Tert-butyl 2-[(2-bromo-5-methoxyphenoxy)methyl]-2,5-dihydro-1H-pyrrole-1-carboxylate (16.4 g, 0.43 mol) was dissolved in toluene (790 mL) and heated at 50° C. for 20 min. To this solution was added AlBN (781 mg, 0.047 mol) and tributyltin hydride (17.9 mL, 0.67 mol). The reaction mixture was stirred at 80° C. for 16 h, cooled to RT, and DBU (10.7 g, 0.70 mol) was added. The resulting suspension was filtered through a pad of silica gel (100 g), and the solids washed with methyl tert-butylether. The filtrate was evaporated and the resulting oil triturated with heptane (10 mL). The crude product was collected via filtration and purified using an ISCO instrument (330 g RediSep® column), eluting with a gradient of ethyl acetate in heptane (from 5%-20%) to afford the title product. MS m/z 249 [M−tBu+H]+
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