Reaction Steps
Diazomethane (˜0.25M in Et2O (prepared according to Aldrich Technical Bulletin AL-180, Aldrich, St. Louis, Mo.); 2.0 mL, 0.500 mmol) was added dropwise to a solution of (4R)-tert-butyl 4-(6-(5-(prop-1-en-2-yl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yloxy)-6-azaspiro[2.5]octane-6-carboxylate (110.4 mg, 0.202 mmol) and palladium(II) acetate (4.54 mg, 0.020 mmol) in DCM (2.0 mL) at 0° C. and the resulting solution was stirred at 0° C. for 30 min. Additional diazomethane (˜0.25M in Et2O; 2.0 mL, 0.500 mmol) was added, and the resulting solution was stirred at 0° C. for 30 min. HOAc (0.069 mL, 1.214 mmol) was added to quench excess diazomethane, and the resulting mixture was stirred at 25° C. for 12 h. The mixture was concentrated onto silica gel and chromatographically purified (ISCO, 12 g silica gel column, 0-60% EtOAc/hexanes, 15 min, 254 nm) to provide (4R)-tert-butyl 4-(6-(5-(1-methylcyclopropyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yloxy)-6-azaspiro[2.5]octane-6-carboxylate (96.3 mg, 0.172 mmol, 85% yield) as a colorless oil: 1H NMR (400 MHz, CDCl3) δ ppm 9.04 (1 H, s), 8.28 (1 H, s), 8.19 (1 H, br. s.), 7.57 (1H, d, J=8.8 Hz), 7.37 (1 H, d, J=8.4 Hz), 5.78 (1 H, d, J=9.0 Hz), 4.68 (1 H, d, J=8.0 Hz), 4.49 (1 H, br. s.), 4.28 (1 H, d, J=11.9 Hz), 4.03 (1 H, d, J=11.3 Hz), 3.70-3.84 (1 H, m), 3.28 (1 H, d, J=13.7 Hz), 2.97 (1 H, t, J=11.2 Hz), 2.57-2.73 (1 H, m), 2.41-2.54 (1 H, m), 2.16-2.28 (1 H, m), 2.07-2.15 (1 H, m), 1.63-1.86 (3 H, m), 1.47 (4 H, s), 1.12 (9H, br. s.), 0.85-0.93 (2 H, m), 0.80 (2 H, br. s.), 0.73 (1 H, br. s.), 0.62 (1 H, br. s.), 0.56 (2 H, br. s.). MS (ESI, pos. ion) m/z: 560.3 (M+1).
