Reaction Steps
To the solution of the product of Example 37 (189 mg, 0.58 mmol) in dichloromethane (2.5 mL) was added Et3N (0.10 mL, 0.72 mmol), and the mixture was cooled to 0° C. CbzCl (0.11 mL, 0.73 mmol) was added dropwise, and the solution was warmed up room temperature for 2 h. The reaction was quenched with aqueous NaCl, extracted with dichloromethane several times. The combined organic layer was dried over MgSO4. After the removal of volatiles, the residue was chromatographed on silica gel using hexanes-EtOAc (3:1) and hexanes-EtOAc (1:1) to yield pure product (138 mg) and starting material (5.81) (75 mg), 86% yield based on the consumed (5.81). Contain two rotamers at rt. 1H NMR (360 MHz, MeOD-d4) δ 7.55-7.48 (m, 1H), 7.38-7.21 (m, 5H), 6.50-6.33 (m, 2H), 5.90 (d, J2,3=5.7 Hz, 0.5H, H2), 5.87 (d, J2,3=5.7 Hz, 0.5H, H2), 5.76 (t, J4,3=J4,5=9.6 Hz, 0.5H, H4), 5.74 (t, J4,3=J4,5=9.6 Hz, 0.5H, H4), 4.99 (ddd, J5,6b=10.9 Hz, J5,4=9.6 Hz, J5,6a=5.6 Hz, H5), 4.39 (dd, J6a,6b=13.0 Hz, J6a,5=5.6 Hz, 0.5H, H6a), 4.35 (dd, J6a,6b=13.0 Hz, J6a,5=5.6 Hz, 0.5H, H6a), 3.07 (dd, J6b,6a=13.0 Hz, J6b,5=10.9 Hz, 0.5H, H6b) 2.97 (dd, J6b,6a=13.0 Hz, J6b,5=10.9 Hz, 0.5H, H6b), 2.00 (s, 3H), 1.99 (s, 3H), 1.87 (s, 3H).
