Potassium Carbonate → 2-(8-Fluoro-1-oxo-1,2-dihydroisoquinolin-6-yl)-2-methylpropanenitrile

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A 500 mL round-bottomed flask was charged with 2-bromo-N-tert-butyl-4-(2-cyanopropan-2-yl)-6-fluorobenzamide (34.5 g, 101 mmol, 1 equiv.) and potassium carbonate (27.9 g, 202 mmol, 2 equiv.) and the flask was subsequently purged with nitrogen (3 times). 1,4-dioxane (242 ml) and water (34.5 ml) were added. The E-2-(2-ethoxyvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (28.0 g, 142 mmol, 1.4 equiv.) was then added by syringe. The reaction mixture was heated to 40° C. To the mixture was added bis(dibenzylideneacetone)palladium (2.33 g, 4.04 mmol, 0.04 equiv.) and tricyclohexylphosphine (2.27 g, 8.09 mmol, 0.08 equiv.) and the resulting mixture was heated with stirring at 90° C. (inner temperature)/100° C. (bath) for 2 h until reaction was complete. The reaction mixture was cooled to ambient temperature and quenched with 20% NaHSO3 solution (150 mL) followed by stirring for 2 hr. The mixture was extracted with EtOAc (2 times), dried over MgSO4, and concentrated under reduced pressure. The resultant product was dissolved with TFA (138 ml) in a 350 mL pressured bottle and heated to 100° C. (bath temp.) for 3 hr. The reaction mixture was transferred to a round-bottomed flask with toluene, and the TFA was removed under reduced pressure, then basified with 20% K2CO3 solution. The reaction mixture was extracted with EtOAc and then with DCM. Crystallization from methyl-tert-butylether afforded 2-(8-fluoro-1-oxo-1,2-dihydroisoquinolin-6-yl)-2-methylpropanenitrile (16.2 g, 69.6% yield) as a brown solid. 1H NMR (300 MHz, DMSO-d6) δ ppm 1.74 (s, 6 H) 6.60 (dd, J=6.99, 1.70 Hz, 1 H) 7.16-7.28 (m, 1 H) 7.36 (dd, J=13.03, 1.70 Hz, 1 H) 7.61 (d, J=1.89 Hz, 1 H) 11.31 (br. s., 1 H).

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