Toluene → 3-(4-chloro-6,7-dihydro-5H-cyclopenta[b]pyridin-2-yl)cyclopent-2-enone

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Reaction Conditions

Reaction Steps

A 250-mL round bottomed flask was charged with 2,4-dichloro-6,7-dihydro-5H-cyclopenta[b]pyridine (1.05 g, 5.58 mmol), 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)cyclopent-2-enone (1.27 g, 6.14 mmol), tetrakis(triphenylphosphine)palladium(0) (0.322 g, 0.28 mmol), and Cs2CO3 (5.45 g, 16.7 mmol). Toluene (30 ml), EtOH (7.5 ml) and water (15 ml) were added. The resulting mixture was stirred under argon at 90° C. for 18 h. After cooling to room temperature, the reaction mixture was diluted with ethyl acetate (150 mL), hexanes (50 mL) and water (25 mL). The aqueous layer was separated and extracted with ethyl acetate (2×100 mL). The combined organic extract was washed with saturated sodium chloride (2×20 mL), dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by chromatography on silica using hexane/ethyl acetate (10:0 to 0:10) as eluent to afford the title compound (0.305 g, 23%) as a yellow solid. MW=233.69. 1H NMR (CDCl3, 500 MHz) δ 7.41 (s, 1H), 6.79 (t, J=2.0 Hz, 1H), 3.13 (t, J=7.5 Hz, 2H), 3.10-3.06 (m, 2H), 3.04 (t, J=7.5 Hz, 2H), 2.62-2.58 (m, 2H), 2.20 (quin, J=7.5 Hz, 2H).

Provenance & Evidence