Ethanol → 6-Thiophen-3-yl-3,4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester

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Reaction Steps

A mixture of bis(benzonitrile)palladium(II) chloride (30 mg, 0.079 mmol) and 1,4-bis(diphenylphosphino)butane (33.6 mg, 0.079 mmol) in toluene (3 mL) was stirred at room temperature for 20 min. To this mixture was added 6-trifluoromethanesulfonyloxy-3,4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester (300 mg, 0.79 mmol, Synth. Commun. 1995, 25, 3255), thiophene-3-boronic acid (131 mg, 1.02 mmol), 1 M aqueous sodium carbonate (1.57 mL, 1.57 mmol), and ethanol (2 mL). This dark mixture was heated to reflux with stirring under nitrogen overnight, cooled to room temperature, diluted with saturated aqueous sodium bicarbonate, and extracted with ethyl acetate (4×). The combined organic extracts were dried over sodium sulfate, filtered through Celite, evaporated, and purified by flash column chromatography (hexanes→5% ethyl acetate/hexanes) to give 252 mg (100%) of the title compound of Example 248, Step A as a pale yellow waxy solid. 1H NMR (CDCl3, 250 MHz) δ 7.47-7.38 (c, 5H), 7.14 (d, 1H), 4.60 (s, 2H), 3.72-3.64 (c, 2H), 2.95-2.82 (c, 2H), 1.52 (s, 9H); MS (TS) 316 (MH+).

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