A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 199d (4.5 g, 1.0 eq., 11.6 mmol), Pin2B2 (7.38 g, 2.5 eq., 29.0 mmol), PdCl2(dppf) (473 mg, 0.05 eq., 0.58 mmol), x-phos (470 mg, 0.1 eq., 1.16 mmol), potassium acetate (3.41 g, 3.0 eq., 34.8 mmol), and dioxane (100 mL). After three cycles of vacuum/argon flush, the mixture was heated at 65° C. for 4 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure to afford crude 199e as a brown-red liquid (4.0 g, purity: 65%). MS-ESI: [M+H]+ 398.3.
