2,4-Dichlorophenyl isocyanate → 1-(2,4-Dichloro-phenyl)-3-((4S,5S)-2,2-dimethyl-4-phenyl-[1,3]dioxan-5-yl)-urea

To a solution of 102 mg (0.49 mmol) of (4S,5S)-amine 1 in pentane (3 mL) was added a solution of 74 mg (0.39 mmol) of 2,4-dichlorophenyl isocyanate in dichloromethane (0.1 mL). A white precipitate was observed and collected via filtration. The crude solid was dissolved in dichloromethane (˜4 mL) and washed with 0.1 N HCl (˜4 mL). The organic layer was washed with brine, dried over magnesium sulfate, filtered, and evaporated to yield 91 mg (59%) of the title compound.