Potassium Carbonate → 4,6-Difluoro-5-(4-(1-hydroxycyclobutyl)phenyl)-1H-indole-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A mixture of 5,5,5′,5′-tetramethyl-2,2′-bi(1,3,2-dioxaborinane) (188.0 mg, 0.55 mmol), oven dried potassium acetate (230.0 mg, 2.34 mmol), and 1-(4-bromophenyl)cyclobutanol (114.0 mg, 0.50 mmol) in 1,4-dioxane (2 mL) was degassed with N2 for 15 min, then treated with [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (20.0 mg, 0.027 mmol). The reaction mixture was subjected to microwave irradiation at 110° C. for 1 hour. The cooled reaction mixture was filtered through celite, rinsed with EtOAc and concentrated to dryness. To the resulting dark solid ((45.0 mg, 0.17 mmol) was added 5-bromo-4,6-difluoro-1H-indole-3-carbaldehyde (45.0 mg, 0.17 mmol), 2 N aqueous potassium carbonate (0.20 mL, 0.40 mmol), toluene (1.5 mL) and EtOH (0.5 mL). The reaction mixture was degassed with N2 for 10 minutes, treated with [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (14.0 mg, 0.019 mmol), and heated in a sealed pressure tube at 110° C. for 2 hours. The reaction mixture was cooled to room temperature and purified by flash chromatography (0-67% EtOAc/heptanes) to give the title compound (37 mg, 65%) as a white solid. MS (ES+) 328.0 (M+H)+. 1H NMR (500 MHz, CD3OD) δ 10.04 (d, J=2.68 Hz, 1 H), 8.15 (s, 1 H), 7.64 (d, J=8.05 Hz, 2 H), 7.48 (d, J=8.05 Hz, 2 H), 7.21 (d, J=9.51 Hz, 1 H), 2.57-2.66 (m, 2 H), 2.39-2.46 (m, 2 H), 2.03-2.12 (m, 1 H), 1.73-1.83 (m, 1 H).

Provenance & Evidence