反応手順
A solution of 2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hex-5-enamide (240 mg, 0.52 mmol) in dichloromethane (4 mL), was treated with chloro-1,5-cyclooctadiene iridium(I) dimer (10.4 mg, 3 mol %) and 1,2-bis(diphenylphosphino) ethane (12.2 mg, 6 mol %). The solution was stirred at room temperature for 30 minutes and then 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (0.152 mL, 1.04 mmol) was added dropwise, and the reaction was stirred overnight at room temperature. The next day, the reaction mixture was poured into water and extracted with ethyl acetate (3×). The combined organic phase was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. Purification of the crude product by flash column chromatography (silica gel, 30-100% ethyl acetate in heptane) gave 2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide as a colorless oil (212 mg, 69%). 1H NMR (CDCl3, 300 MHz) δ 7.24 (d, J=2 Hz, 1H), 7.20 (d, J=8.5 Hz, 1H), 7.12 (dd, J1=8.5 Hz, J2=2 Hz, 1H), 6.97 (s, NH, 1H), 5.48 (s, NH, 1H), 4.32 (m, 2H), 3.02 (m, 2H), 2.84 (m, 1H), 2.47 (tt, J1=12.5 Hz, J2=3 Hz, 1H), 2.01 (s, 3H), 1.86 (m, 2H), 1.30-1.55 (m, 6H), 1.34 (s, 9H), 1.24 (s, 12H), 1.02-1.22 (m, 1H), 0.75 (t, J=7.5 Hz, 2H).
