To a mixture of NaOH (25 g) and 15.7 g of activated molecular sieves in 1159 mL of THF at 0° C. was added a 1159 mL THF solution of diethyl benzyl(hydroxy)propanedioate (153 g). After 5 min, to this mixture was added [(1R)-1-isocyanatoethyl]benzene (118 g). The mixture was stirred at 0° C. for 30 min and then warmed to ambient temperature and stirred for 4 h. The reaction mixture was directly purified using a Biotage silica gel chromatography system (5-30% ethyl acetate in hexanes) to give the title compound.
