To a mixture of phthalimide (1.43 g, 9.72 mmol), ((R)-1-hydroxymethyl-butyl)-carbamic acid tert-butyl ester (prepared according to the procedure described in Tetrahedron Letters (1987), 28(48), 6069-72) (1.97 g, 9.69 mmol) and triphenylphosphine (2.55 g, 9.72 mmol) in DCM (25 mL) at 0° C. is added DEAD (1.6 mL, 10.2 mmol) dropwise. The reaction mixture is stirred at RT overnight. The reaction mixture is adsorbed onto silica gel and purification by column chromatography (SiO2, EtOAc/iso-hexane, gradient of 0-15% EtOAc) affords the title compound as white solid. [M+H]+ 233.
