Toluene → Methyl 1-[2-(4'-nitro-1,1'-biphenyl-4-yl)-2-oxoethyl]cyclopentanecarboxylate

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To a 150 mL 3-neck flask fitted with a reflux condenser was added methyl 1-[2-(4-bromophenyl)-2-oxoethyl]cyclopentanecarboxylate (1.58 g, 4.64 mmol), 4-nitro phenyl boronic acid (0.93 g, 5.6 mmol), toluene (45 mL), and dioxane (13 mL), followed by the addition of a saturated aqueous sodium carbonate solution (13 mL). The mixture was degassed using argon and 1,2-bis[(diphenylphosphino)ferrocene]dichloropalladium(II) (0.19 g, 0.23 mmol) was added, followed by an additional 15 minutes of degassing, and the deep red reaction mixture was heated to 85° C. for 16 h. The very darkly colored reaction mixture was allowed to cool, and then was diluted with ethyl acetate (100 mL) and saturated aqueous sodium chloride solution (100 mL). The layers were separated and the aqueous layer was extracted twice with ethyl acetate (50 mL). The combined organic layer was washed with saturated aqueous sodium chloride solution (100 mL), dried over anhydrous magnesium sulfate, and filtered under reduced pressure through 2 cm Celite®/2 cm silica. The filtrate was concentrated under reduced pressure, leaving a dark red-brown oil, that was purified by flash chromatography (4:1/hexane:ethyl acetate, then 3:1/hexane:ethyl acetate, then 2:1/hexane:ethyl acetate) to afford methyl 1-[2-(4′-nitro-1,1′-biphenyl-4-yl)-2-oxoethyl]cyclopentanecarboxylate (1.65 g, 93%). LC-MS ret. time 3.56 min, m/z 368.0 (MH+); 1H NMR (300 MHz, CDCl3) δ 1.56-1.85 (overlapping signals, 6H), 2.23-2.37 (m, 2H), 3.45 (s, 2H), 3.67 (s, 3H), 7.70 (d, 2H), 7.77 (d, 2H), 8.06 (d, 2H), 8.34 (d, 2H).

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