To a solution of alcohol 1 (160 mg, 55 mmol) in DCM (3 mL) at 0° C. was added carbonyldiimidazole (CDI) (107 mg, 0.66 mmol) and the reaction was stirred for 1 h. Then N-methylpiperazine (80 mg, 0.72 mmol) and DMAP (68 mg, 0.55 mmol) were added and stirred for 12 h. Solvent was removed and the residue was purified by column chromatography (DCM/MeOH) to give the carbamate 40a as a viscous oil in 88% yield (191 mg). TLC Rf: 0.54 (10% MeOH/DCM); 1H NMR (300 MHz, CDCl3): δ 5.34 (t, 3H), 5.08 (m, 3H), 4.59 (d, 2H), 3.49 (m, 4H), 2.35 (m, 4H), 2.29 (s, 3H), 2.10-1.97 (m, 12H), 1.70 (s, 3H), 1.67 (s, 3H), 1.59 (s, 9H); LCMS: MS (m/z): 417 (M+H).
