[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[O:9][C:10]([CH3:16])=[C:11]([CH2:13][CH2:14]I)[N:12]=2)=[CH:4][CH:3]=1.S1CCCCS1.[Li]CCCC.[S:28]1[CH2:33][CH2:32][CH2:31][S:30][CH2:29]1.CN1CCCN(C)C1=O>C1COCC1.O>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[O:9][C:10]([CH3:16])=[C:11]([CH2:13][CH2:14][CH:29]3[S:30][CH2:31][CH2:32][CH2:33][S:28]3)[N:12]=2)=[CH:4][CH:3]=1Add a cold (−78° C.) solution of 2-(4-bromo-phenyl)-4-(2-iodo-ethyl)-5-methyl-oxazole (See Intermediate 30) (1.05 g, 2.67 mmol) in 15 mL THF to a cold (−78° C.) solution of dithiane anion [Preparation: Add n-BuLi (7.5 mL, 12 mmol, 1.6M in hexanes) to a −20° C. solution of 1,3-dithiane (1.92 g, 15.9 mmol) in 25 mL THF. Stir 20 min at −78° C. and add 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU, 4.03 g, 31.4 mmol).] Stir the reaction mixture at −78° C. for 15 min. Add water and warm to room temperature. Add dichloromethane, and separate the layers. Dry the crude organic extracts over MgSO4, filter and concentrate. Purify on silica gel 0-10% EtOAc/Hexanes to give 2-(4-bromo-phenyl)-4-(2-[1,3]dithian-2-yl-ethyl)-5-methyl-oxazole (0.672 g, 66%). MS (m/e): 384 (M+1).
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