Reaction Steps
In a 100 mL round-bottom flask was dissolved (5S,6S,9R)-5-azido-6-(2,3-difluorophenyl)-9-(triisopropylsilyloxy)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine (0.732 g, 1.549 mmol) (crude) in tetrahydrofuran (8 mL) to give a colorless solution. TBAF (1.859 mL, 1.859 mmol) was added, and the resulting light yellow solution was stirred at room temperature for 1.5 h. LCMS indicated complete conversion. Tetrahydrofuran was removed and the residue was diluted with water and ethyl acetate. The layers were separated. The organic layer was washed with brine, dried, and concentrated to give a light yellow oil. Purification by FCC up to 60% ethyl acetate/hexane afforded the desired product (crude weight: 480 mg) as a colorless oil. Smaller scale purification afforded an analytical sample: MS (ESI) [M+H+]=317.22; 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 8.51 (dd, J=4.91, 1.38 Hz, 1H) 7.99 (d, J=7.30 Hz, 1H) 7.35 (dd, J=7.81, 5.04 Hz, 1H) 7.06-7.20 (m, 2H) 6.94-7.05 (m, 1H) 5.91 (br. s., 1H) 5.03 (d, J=10.32 Hz, 1H) 4.92 (dd, J=11.21, 2.39 Hz, 1H) 2.84-3.02 (m, 1H) 2.37-2.49 (m, 1H) 2.25-2.36 (m, 1H) 2.07-2.17 (m, J=14.38, 4.94, 3.05, 3.05 Hz, 1H) 1.40-1.64 (m, 1H); 13C NMR (101 MHz, CHLOROFORM-d) δ ppm 158.48 (s, 1C) 152.19-149.87 (dd, J=13.10 and 221 Hz, 1C) 149.72-147.42 (dd, J=13.87 and 219 Hz, 1C) 146.16 (s, 3C) 133.67 (s, 2C) 133.23 (s, 1C) 132.66 (d, J=10.79 Hz, 1C) 124.43 (dd, J=6.94, 3.85 Hz, 2C) 123.84 (br. s., 1C) 122.89 (s, 2C) 115.98 (d, J=17.73 Hz, 2C) 70.94 (s, 3C) 65.67 (s, 1C) 45.43 (br. s., 1C) 35.71 (s, 3C) 33.45 (s, 2C); 19F NMR (376 MHz, CHLOROFORM-d) δ ppm −137.55-−137.20 (m, 1F) −142.28-−141.89 (m, 1F).
