Br[C:2]1[C:7]([F:8])=[CH:6][CH:5]=[CH:4][N:3]=1.[F:9][C:10]1[CH:15]=[CH:14][C:13]([N+:16]([O-:18])=[O:17])=[CH:12][C:11]=1B1OC(C)(C)C(C)(C)O1.[F-].[K+].O>O1CCCC1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd]>[F:8][C:7]1[C:2]([C:11]2[CH:12]=[C:13]([N+:16]([O-:18])=[O:17])[CH:14]=[CH:15][C:10]=2[F:9])=[N:3][CH:4]=[CH:5][CH:6]=1
To 2-bromo-3-fluoropyridine (1.198 g, 6.807 mmol), prepared according to the procedure of Queguiner et al. (Tetrahedron, 1983, 39, 2009-21), and 2-(2-fluoro-5-nitrophenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (2.72 g, 10.2 mmol), in dry tetrahydrofuran (20 ml) under an atmosphere of nitrogen, was added potassium fluoride (2.0 g), water (1.0 ml) and tris(dibenzylideneacetone)dipalladium(0) (0.139 g). The mixture was thoroughly degassed, then a solution of tri-tert-butylphosphine (3.05 ml of a 0.1 M solution in 1,4-dioxane) was added. The mixture was stirred at 35° C. for 18 h. The reaction was partitioned between dichloromethane and water, the organic phase separated, evaporated, and the residue chromatographed (silica gel; CH2Cl2) to afford 3-fluoro-2-(2-fluoro-5-nitrophenyl)pyridine as a white solid (1.485 g): MS (ES+) m/z 236 M+H]+.
Wird geladen…
