Under argon atmosphere, ethyl 2-(tert-butoxy)-2-[2,5-dimethyl-4-(tetramethyl-1,3,2-dioxaborolan-2-yl)thiophen-3-yl]acetate (28f) (50 mg, 0.12 mmol), 5,6,7,8-tetrahydronaphthalen-2-yl trifluoromethanesulfonate (39a) (41.4 mg, 0.15 mmol) and sodium carbonate (13.7 mg, 0.13 mmol) were dissolved in dimethylformamide (2.5 mL) and water (0.85 mL). The solution was degassed under argon for 10 minutes and Tetrakis(triphenylphosphine)palladium (28.5 mg, 0.02 mmol) was added. The reaction was heated and shaken at 100° C. for 4 hours. After cooling at room temperature, water was added and the mixture was partitioned between ethyl acetate and water. The organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The crude material was purified by preparative TLC (cyclohexane/ethyl acetate: 9/1) to provide the desired product (39b) (40 mg, 0.1 mmol, 77%).
