Methanesulfonyl chloride (0.32 ml, 4.12 mmol) and TEA (0.57 ml, 4.12 mmol) were added to a solution of (R)-2-(2-hydroxy-1-phenylethyl)isoindoline-1,3-dione (1.0 g, 3.7 mmol) in DCM (20 ml) and were stirred overnight. The resulting solution was washed with water (3 × 20 ml) and dried over anhydrous sodium sulphate. The solvents were removed under reduced pressure and the residue was used in the subsequent reaction without further purification. Yield 1.22 g (94%).

¹H NMR (400 MHz, 298 K, CDCl₃) δ_H 7. 84 (2H, dd, ³J_HH = 5.4 Hz J_HH = 3.1 Hz, Pht), 7.72 (2H, dd, ³J_HH = 5.5 Hz, ³J_HH = 3.0 Hz, Pht), 7.55 – 7.48 (2H, m, Ph), 7.40 – 7.31 (3H, m, Ph), 5.68 (1H, dd, ³J_HH = 10.5 Hz ²J_HH = 5.4 Hz, CH), 5.41 (1H, t, ³J_HH = 10.4 Hz, CH₂), 4.78 (1H, dd, ³J_HH = 10.4 Hz, ²J_HH = 5.4 Hz, CH₂), 2.98 (3H, s, SO₃CH₃).

¹³C NMR (100 MHz, 298 K, CDCl₃) δ_C 168.22 (C=O), 135.19, 134.44 (Pht), 131.77, 129.19, 128.20 (Ph), 123.66 (Pht), 67.23 (CH₂), 54.25 (CH), 37.67 (SO₃CH₃).

MS (ESI⁺) m/z 368.0 ([M+Na]⁺), 250.1 ([M-SO₃CH₃]⁺)