[Br:1][C:2]1[CH:7]=[C:6]([O:8][CH3:9])[C:5]([OH:10])=[C:4]([O:11][CH3:12])[CH:3]=1.[OH-].[K+].C(OP([C:23](Br)([F:25])[F:24])(=O)OCC)C>CC#N.O>[Br:1][C:2]1[CH:3]=[C:4]([O:11][CH3:12])[C:5]([O:10][CH:23]([F:25])[F:24])=[C:6]([O:8][CH3:9])[CH:7]=15-Bromo-2-(difluoromethoxy)-1,3-dimethoxybenzene was synthesized from 4-bromo-2,6-dimethoxyphenol according to the procedure of Zafrani, Y. Tetrahedron 2009, 65, 5278 as follows. To a solution of 4-bromo-2,6-dimethoxyphenol (1.08 g, 4.6 mmol) in MeCN (27 mL) was added a solution of KOH (5.0 g, 89 mmol) in H2O (27 mL). The mixture was immediately cooled over a −78° C. bath and diethyl(bromodifluoromethyl)phosphonate (1.6 mL, 8.9 mmol) was added. The flask was sealed with a septum and the cold bath was removed. The mixture was stirred for a total of 3.5 hrs during which time the septum was ejected from the flask. The reaction was diluted with EtOAc and the layers were separated. The aqueous layer was extracted with EtOAc and the combined organics were washed with 1 M NaOH, H2O and brine then dried over Na2SO4 and concentrated in vacuo. Purification by chromatography (0-30% EtOAc-hexanes) provided 5-bromo-2-(difluoromethoxy)-1,3-dimethoxybenzene as a white solid (0.808 g, 62% yield).
読み込み中…
