To a magnetically stirred solution of N-t-butyloxycarbonyl-2(R)-(1(S)-t-butyldimetylsilyloxy-2-chloroethyl)aziridine (36.0 mg, 0.107 mmol) in toluene was added copper bromide dimethyl sulfide complex (11.0 mg, 0.054 mmol) at rt under N2. The reaction mixture was cooled to −78° C. then treated with a 2 M solution of PhMgCl in THF (0.54 mL, 1.072 mmol). The resulting mixture was warmed to −20° C. and stirred overnight. The reaction mixture was treated with sat NH4Cl (4 mL) and extracted with EtOAc(5 mL×3). The combined organic layers were washed with brine (50 mL), dried over anhydrous magnesium sulfate, filtered, concentrated and column-chromatographed (3% EtAc in n-Hex) to provide 2(S)-t-butyldimetylsilyloxy-3(R)-(t-butyloxycarbonyl)amino-1-chloro-4-phenylbutane (33.5 mg) as a colorless oil.
