To a solution of (2-hydroxy-2-phenyl-ethyl)-carbamic acid tert-butyl ester (34.4 g, 145.0 mmol), phthalimide (21.3 g, 145 mmol), and PPh3 (49.4 g, 188.5 mmol) was added drop-wise DEAD (32.8 g, 188.5 mmol) under stirring at 0° C. After addition, the mixture was stirred at room temperature for an additional 1 hour. The mixture was concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (petroleum ether:ethyl acetate, 20:1 to 5:1) to give [2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-2-phenyl-ethyl]-carbamic acid tert-butyl ester as a white solid. (Yield 39 g, 74%) 1H NMR (300 MHz, CDCl3): δ 7.88-7.80 (m, 2H), 7.74-7.68 (m, 2H), 7.49-7.47 (m, 2H), 7.38-7.26 (m, 3H), 5.56-5.50 (m, 1H), 4.83 (brs, 1H), 4.28-4.22 (m, 1H), 3.93-3.87 (m, 1H), 1.35 (s, 9H). LC-MS: [M-Boc+H]+ 267.
