Tris(1,1-dimethylethyl)phosphine → 4,2'-Difluoro-5'-nitrobiphenyl-2-carbonitrile

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Reaction Steps

A mixture of 2-bromo-5-fluorobenzonitrile (20 g, 100 mmol), 2-(2-fluoro-5-nitrophenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (from Example 2, step d) (34.7 g, 130 mmol) and potassium fluoride (19.2 g, 330 mmol) in tetrahydrofuran (350 ml) and water (20 ml) was degassed with nitrogen for 30 min then treated with tris(dibenzylideneacetone)-dipalladium(0) (1.83 g, 2 mmol) followed by tri-tert-butylphosphine (4 ml of a 0.2 M solution in 1,4-dioxane, 0.8 mmol). This mixture was stirred at ambient temperature for 30 min before heating at 50° C. for 18 h. The resulting dark suspension was cooled to ambient temperature, diluted with 0.5 M sodium hydroxide (2.5 l) and stirred at ambient temperature for 4 h. The solid was collected by filtration, washed with water and dried under suction to afford 4,2′-difluoro-5′-nitrobiphenyl-2-carbonitrile as a black solid (28.1 g, >100%) contaminated with dibenzylideneacetone: 1H NMR (360 MHz, CDCl3) δ 7.38-7.56 (4H, m), 8.33-8.40 (2H, m).

Provenance & Evidence