To 3-amino-2,2-dimethylpropanoic acid, hydrochloride salt (250 mg, 1.63 mmol, 1 eq.) in dichloromethane (4 mL, 0.4 M) was added diisopropylethylamine (859 μL, 4.88 mmol, 3 eq.) followed by (9H-fluoren-9-ylmethoxy)carbonyl chloride (473 mg, 1.79 mmol, 1.1 eq.) The reaction was stirred for 18 hours and then concentrated in vacuo. The residue was taken up in ethyl acetate (3 mL) and washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine. The organic layer was dried over sodium sulfate, filtered, and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #93 (250 mg, 45%) as an oil. 1H NMR (400 MHz, DMSO-d6) δ 12.22 (s, 1H), 7.89 (d, J=7.4 Hz, 2H), 7.72 (d, J=7.4 Hz, 2H), 7.38-7.44 (m, 2H), 7.27-7.35 (m, 3H), 4.18-4.30 (m, 3H), 3.16 (d, J=6.2 Hz, 2H), 1.05 (s, 6H).
