To a solution of t-butyl 4-bromomethyl-3-nitrobenzoate (2.27 g, 7.2 mmol) (Int. J. Peptide Res., 36, 31 (1990)) in DMF (25 mL) was added a suspension of potassium t-butyl methyl iminodicarboxylate (J.C.S. Perkin I, 1088, (1977)) (1.56 g, 7.3 mmol) in DMF (20 mL). The dark brown solution was stirred 1 h and poured into water and extracted with ethyl acetate. The combined organic layers were washed with water, dried (sodium sulfate) and concentrated to give a pale orange oil which was purified by flash chromatography (silica gel, 20% ethyl acetate/hexane) to give the title compound (2.15 g, 73%). 1H NMR (400 MHz, CDCl3) δ8.65 (s, 1H), 8.2 (d, 1H), 7.45 (d, 1H), 5.3 (s, 2H), 3.8 (s, 3H), 1.6 (s, 9H), 1.45 (s, 9H).
