1.1: (R)-diphenylprolinol trimethylsilyl ether; chloroacetic acid / toluene 2.1: caesium carbonate / 4 h / 0 - 20 °C 3.1: -15 °C 4.1: trifluoroacetic acid / toluene / 4 h / 20 °C 5.1: oxalyl dichloride; N,N-dimethyl-formamide / toluene / 0.33 h / 20 °C 6.1: trimethylsilylazide / toluene / 0.33 h / 20 °C 7.1: acetic acid / 48 h / 20 °C 8.1: chloro-trimethyl-silane; zinc / ethanol / 70 °C 8.2: 0 °C 9.1: potassium carbonate / 20 °C View Scheme

Multi-step reaction with 3 steps 1: (R)-diphenylprolinol trimethylsilyl ether; chloroacetic acid / toluene2: caesium carbonate / 4 h / 0 - 20 °C3: -15 °C  

Multi-step reaction with 2 steps 1: (S)-2-(diphenyl(trimethylsilyloxy)methyl)pyrrolidine; chloroacetic acid / dimethyl sulfoxide / 20 °C2: 1,8-diazabicyclo[5.4.0]undec-7-ene; lithium chloride / acetonitrile / 70 °C / Inert atmosphere