Reaction #2460311

Reaction equation

butyl 4′-bromobiphenyl-3-carboxylate

4-trifluoromethylbenzene boronic acid

potassium carbonate

18-crown-6

toluene

toluene

→

3-butoxycarbonyl-4′-trifluoromethyl-p-terphenyl

Solvents

water

Conditions

Workup

1. 1
   Otherby sparging with nitrogen for 10 min
2. 2
   Temperaturethe mixture was heated
3. 3
   Temperatureat reflux for 44 h
4. 4
   workup.ADDITIONwere added
5. 5
   OtherThe organic layer was separated
6. 6
   Washwashed with water and with brine
7. 7
   Dryingdried (MgSO4)
8. 8
   Concentrationconcentrated
9. 9
   OtherThe product was purified by column chromatography
10. 10
    Otherfollowed by recrystallization from heptane
11. 11
    Otherto provide 0.96 g (45% of theory) of a white powder

Procedure

Finally, 3-butoxycarbonyl-4′-trifluoromethyl-p-terphenyl (CS-18) was prepared. A mixture of butyl 4′-bromobiphenyl-3-carboxylate (1.80 g, 5.4 mmol), 4-trifluoromethylbenzene boronic acid (1.08 g, 5.7 mmol), potassium carbonate (2.24 g, 16 mmol), toluene (30 mL), and 18-crown-6 (20 mg) was deaerated by sparging with nitrogen for 10 min. Tetrakis(triphenylphosphine)-palladium(0) (0.12 g, 0.11 mmol) was added, and the mixture was heated at reflux for 44 h. Additional tetrakis(triphenylphosphine)palladium(0) (0.10 g, 0.10 mmol) was added, and the reaction was continued for 24 h. The mixture was cooled to ambient, and toluene (30 mL) and water (30 mL) were added. The organic layer was separated, washed with water and with brine, dried (MgSO4), passed through short column of silica gel, and concentrated to deposit a gold solid. The product was purified by column chromatography followed by recrystallization from heptane to provide 0.96 g (45% of theory) of a white powder. 1H NMR (CDCl3): δ 1.00 (t, 3H), 1.5 (m, 2H), 1.8 (m, 2H), 4.36 (t, 2H), 7.51 (t, 1H), 7.7 (m, 8H), 7.80 (d, 1H), 8.03 (d, 1H), 8.30 (s, 1H).

Source