Water → 2,5-Di([1,1'-biphenyl]-3-yl)-3,4-bis(4-bromophenyl)cyclopenta-2,4-dienone

Participants

Reaction Conditions

Reaction Steps

To a degassed solution of 2.84 g of 4,4′-dibromobenzil (7.73 mmol) and 2.80 g of 1,3-di(biphenyl-3-yl)propan-2-one (7, 7.73 mmol) in 30 ml of tert-butanol was added, at 80° C., a methanolic tetrabutylammonium hydroxide solution (1 M, 2.84 ml, 2.84 mmol). The reaction solution was stirred at 80° C. for 20 minutes and then stopped by adding water. Extraction was effected three times with dichloromethane, and the collected organic phases were washed with saturated sodium chloride solution and dried over magnesium sulfate before the solvent was distilled off under reduced pressure. The crude product was purified by column chromatography (silica gel, eluent: hexane with 20% DCM) and gave 2.85 g of the tetraarylcyclopentadienone 8a as a violet wax (53%, 4.10 mmol). Elemental analysis measured: C 70.5; H 3.3% (calculated for C41H26Br2O: C, 70.9; H, 3.8%); 1H NMR (700 MHz, d8-THF) δ=7.51-7.49 (m, 4H, CH), 7.49-7.46 (m, 4H, CH), 7.41 (dd, J=8.2, 1.1 Hz, 4H, CH), 7.36 (t, J=7.8 Hz, 4H, CH), 7.32 (t, J=8.0 Hz, 2H, CH), 7.29-7.25 (m, 2H, CH), 7.25-7.22 (m, 2H, CH), 7.01-6.99 (m, 4H, CH); 13C NMR (175 MHz, d8-THF) δ=154.28, 141.92, 141.83, 133.58, 132.72, 132.34, 132.30, 132.12, 129.99, 129.89, 129.71, 129.53, 128.26, 127.80, 127.21, 126.74, 123.92; MS (FD, 8 kV): m/z (%): 693.8 (100) [M+] (calculated for C41H26Br2O: 694.0); Rf (hexane with 6% ethyl acetate)=0.47.

Provenance & Evidence