1.1: sec.-butyllithium; (-)-sparteine / tert-butyl methyl ether; cyclohexane / 3 h / -78 - -74 °C / Inert atmosphere 2.1: zinc(II) chloride / diethyl ether; tert-butyl methyl ether; cyclohexane / 0.5 h / -74 °C / Inert atmosphere 2.2: 16 h / 20 °C / Inert atmosphere View Scheme

1: (R)-N-Boc-2-phenylpyrrolidine With sec.-butyllithium; (-)-sparteine in diethyl ether; cyclohexane T=-78°C; 6 h; Inert atmosphere; 2: carbon dioxide in diethyl ether; cyclohexane T=-78 - 20°C; 3: With hydrogenchloride; water in diethyl ether; cyclohexane enantioselective reaction;

1: (R)-N-Boc-2-phenylpyrrolidine With sec.-butyllithium; (1R,2R)-N,N'-bis-(3,3-dimethyl-butyl)-N,N'-dimethyl-cyclohexane-1,2-diamine in diethyl ether; cyclohexane T=-78°C; 6 h; Inert atmosphere; 2: carbon dioxide in diethyl ether; cyclohexane T=-78 - 20°C; 3: With hydrogenchloride; water in diethyl ether; cyclohexane enantioselective reaction;

trifluoroacetic acid in dichloromethane T=0°C; Inert atmosphere;