[F:1][C:2]1[CH:8]=[C:7]([F:9])[C:6]([N+:10]([O-:12])=[O:11])=[CH:5][C:3]=1[NH2:4].[C:13]1(B(O)O)[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.C(N(CC)CC)C>ClCCl.C([O-])(=O)C.[Cu+2].C([O-])(=O)C>[F:1][C:2]1[CH:8]=[C:7]([F:9])[C:6]([N+:10]([O-:12])=[O:11])=[CH:5][C:3]=1[NH:4][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1
A mixture of 2,4-difluoro-5-nitroaniline (3.00 g, 17.23 mmol) (see EP0379894 A3), phenylboronic acid (6.30 g, 51.69 mmol), copper(II) acetate (3.13 g, 17.23 mmol) and 4 Å molecular sieves (3.0 g) in dichloromethane (170.0 mL) and triethylamine (12.01 mL, 43.08 mmol) was placed in a round bottomed flask. The resulting suspension was stirred under at room temperature under a dry ambient atmosphere 50 h. The mixture was filtered through diatomaceous earth and the solvent was evaporated. Additional phenylboronic acid (6.30 g, 51.69 mmol), copper(II) acetate (3.13 g, 17.23 mmol), molecular sieves (3.00 g) triethylamine (12.01 mL, 43.08 mmol), and dichloromethane (170.00 mL) were added and the slurry was stirred for 12 h. The mixture was again filtered through diatomaceous earth and the solvent was evaporated. The resulting residue was re-dissolved in EtOAc, adsorbed on silica and flash chromatographed (15% EtOAc/hexanes) to give 2,4-difluoro-5-nitro-N-phenylaniline as an orange solid (3.92 g, 91% yield).
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