Reaction Steps
A solution of 2-acetylamino-2-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2]bipyridinyl-4-yl)-hex-5-enoic acid, tert-butylamide (1.0 g, 2.38 mmol) in dichloromethane (10 mL) was treated with chloro-1,5-cyclooctadiene iridium(I) dimer (48 mg, 3 mol %) and 1,2-bis(diphenylphosphino)ethane (57 mg, 6 mol %) under an atmosphere of nitrogen. The solution was stirred at room temperature for 30 minutes and then 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (609 mg, 0.69 mL, 4.76 mmol) was added dropwise, and the reaction was then stirred overnight at room temperature. The reaction 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 by flash column chromatography (silica gel, 10-40% ethyl acetate in heptane) gave the title compound as a white solid (1.07 g, 82%); 1H NMR (CDCl3, 300 MHz) δ 8.05 (d, J=2 Hz, 1H), 7.35 (dd, J1=9.0 Hz, J2=2.5 Hz, 1H), 6.96 (br s, NH, 1H), 6.53 (d, J=9.0 Hz, 1H), 5.78 (m, 1H), 5.46 (br s, NH, 1H), 4.36 (d, J=13 Hz, 1H), 4.12 (d, J=13 Hz, 1H), 2.83 (td, J1=13.5 Hz, J2=5 Hz, 1H), 2.72 (td, J1=12.5 Hz, J2=2 Hz, 2H), 2.42 (tt, J1=12 Hz, J2=3 Hz, 1H), 1.97 (s, 3H), 1.77 (m, 2H), 1.32-1.48 (m, 4H), 1.28 (s, 9H), 1.20 (s, 12H), 1.03-1.25 (m, 2H) and 0.72 (t, J=7.5 Hz, 2H); MS (+CI): m/z for C28H46BClN4O4: expected 548.3. found 549.3 (M+H)+, 571.3 (M+Na)+.
