A vial was charged with tert-butyl azetidin-3-ylmethylcarbamate (25 mg, 0.12 mmol), i-Pr2NEt (31 μL, 0.17 mmol) and a flea stir bar. A solution of 2-adamantyl chloroformate in CH2Cl2 (1.5 mL, 17 mg mL−1, 0.12 mmol) was added. The mixture was stirred overnight at rt. A 10-mL ChemElut cartridge (Varian Inc. catalog number 12198007) was wetted with 5% aq HCl (5 mL) and allowed to stand for 5 min. The reaction mixture was applied to the cartridge and eluted with ether (20 mL). The eluate was evaporated to dryness and the residue was purified by preparative HPLC to afford the title compound (10 mg, 23%). 1H NMR (CDCl3) δ 1.42 (s, 9H), 1.5-2.0 (14H), 2.76 (m, 1H), 3.35 (m, 2H), 3.67 (m, 2H), 4.03 (m, 2H), 4.68 (m, 1H), 4.78 (s, 1H); LC-MS Method 1 tR=2.08 min, m/z=387, 365, 309.
