3-bromo-2-phenyl-4H-chromen-4-one → {1-[4-(4-oxo-2-phenyl-4H-chromen-3-yl)-phenyl]-cyclobutyl}-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a round-bottom flask was added 3-bromo-2-phenyl-1-benzopyran-4-one (27.1 mg, 0.09 mmol) and {1-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-cyclobutyl}-carbamic acid tert-butyl ester (50.4 mg, 0.135 mmol) in toluene:ethanol (4:1, 2.5 mL) and 2 M aqueous sodium carbonate (1 mL). The solution was degassed for 20 minutes, after which time, tetrakis(triphenylphosphine) palladium (5.2 mg, 5 mol %) was added. The reaction mixture was heated to 80° C. using an oil bath with a water cooled reflux condenser, while stirring for 21 hours. The reaction mixture cooled to RT, suspended in ethyl acetate and washed with brine, dried (MgSO4), filtered, and concentrated in vacuo. The resulting residue was purified by silica gel chromatography (10:1 to 5:1 hexane:EtOAc gradient) to give a white solid (12.2 mg, 94%). 1H-NMR (400 MHz, CDCl3) δ 8.30 (d, 1H), 7.66 (dd, 1H), 7.53 (dd, 1H), 7.38-7.45 (m, 3H), 7.30-7.36 (m, 3H), 7.27 (d, 2H), 7.19 (d, 2H), 5.11 (bs, 1H), 2.35-2.58 (m, 4H), 1.91-2.09 (m, 1H), 1.77-1.88 (m, 1H), 1.38 (bs, 9H).

Provenance & Evidence